PDZ domain of membrane palmitoylated proteins 3 (MPP3), MPP4, and MPP7, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of MPP3, MPP4, and MPP7, and related domains. MPP3 (also known as MAGUK p55 subfamily member 3, erythrocyte membrane protein p55, or EMP55), MPP4 (also known as MAGUK p55 subfamily member 4 or Discs large homolog 6), and MPP7 (also known as MAGUK p55 subfamily member 7) are membrane-associated guanylate kinase (MAGUK)-like proteins. MPP3 is part of a cell adhesion protein complex including tumor suppressor CADM1 and actin-binding protein 4.1B. Participation in the Crumbs cell polarity complex has also been demonstrated for MPP7 in epithelial cells, and for MPP3 and MPP4 in the retina. MPP4 is needed for proper localization of plasma membrane calcium ATPases and maintenance of calcium homeostasis at the rod photoreceptor synaptic terminals. Binding partners of the MPP3 PDZ domain include nectin-3, serotonin 5-hydroxytryptamine, 5-HT(2C) receptor, and a cell adhesion protein, TSLC1 (tumor suppressor in lung cancer 1); fragments of MPP4 having the PDZ domain bind CRB (PDZ-SH3-GUK) and GABA transporter GAT1 (PDZ-SH3). PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MPP1-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958656029 136 KIVRLVKNKEPLGATIRRDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLKII 215
Cdd:cd06799     1 KIVRLVKNNEPLGATIKRDEKTGAIVVARIMRGGAADRSGLIHVGDELREVNGISVEGKDPEEVIQILANSQGPITFKLI 80

                  .
gi 1958656029 216 P 216
Cdd:cd06799    81 P 81

domain in receptor targeting proteins Lin-2 and Lin-7;

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|..
gi 1958656029   71 LAEDVMEELQAA-SVHSDERELLQLLSTPHLRAVLMVHDTVAQKNFDPVLPP 121
Cdd:smart00569   2 RLLELLEELQSLlSPSEDLQELRRLLQSPHLQALLKIHDKVAETELDPPLPE 53

PDZ domain of membrane palmitoylated proteins 3 (MPP3), MPP4, and MPP7, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of MPP3, MPP4, and MPP7, and related domains. MPP3 (also known as MAGUK p55 subfamily member 3, erythrocyte membrane protein p55, or EMP55), MPP4 (also known as MAGUK p55 subfamily member 4 or Discs large homolog 6), and MPP7 (also known as MAGUK p55 subfamily member 7) are membrane-associated guanylate kinase (MAGUK)-like proteins. MPP3 is part of a cell adhesion protein complex including tumor suppressor CADM1 and actin-binding protein 4.1B. Participation in the Crumbs cell polarity complex has also been demonstrated for MPP7 in epithelial cells, and for MPP3 and MPP4 in the retina. MPP4 is needed for proper localization of plasma membrane calcium ATPases and maintenance of calcium homeostasis at the rod photoreceptor synaptic terminals. Binding partners of the MPP3 PDZ domain include nectin-3, serotonin 5-hydroxytryptamine, 5-HT(2C) receptor, and a cell adhesion protein, TSLC1 (tumor suppressor in lung cancer 1); fragments of MPP4 having the PDZ domain bind CRB (PDZ-SH3-GUK) and GABA transporter GAT1 (PDZ-SH3). PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MPP1-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958656029 136 KIVRLVKNKEPLGATIRRDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLKII 215
Cdd:cd06799     1 KIVRLVKNNEPLGATIKRDEKTGAIVVARIMRGGAADRSGLIHVGDELREVNGISVEGKDPEEVIQILANSQGPITFKLI 80

                  .
gi 1958656029 216 P 216
Cdd:cd06799    81 P 81

Domain present in PSD-95, Dlg, and ZO-1/2; Also called DHR (Dlg homologous region) or GLGF (relatively well conserved tetrapeptide in these domains). Some PDZs have been shown to bind C-terminal polypeptides; others appear to bind internal (non-C-terminal) polypeptides. Different PDZs possess different binding specificities.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958656029  135 VKIVRLVKNKEPLGATIR-RDEHSGAVVVARIMRGGAADRSGLvHVGDELREVNGITVLHKRPDEISQILAQSQGSITLK 213
Cdd:smart00228   2 PRLVELEKGGGGLGFSLVgGKDEGGGVVVSSVVPGSPAAKAGL-RVGDVILEVNGTSVEGLTHLEAVDLLKKAGGKVTLT 80

                   ...
gi 1958656029  214 IIP 216
Cdd:smart00228  81 VLR 83

L27 domain; The L27 domain is found in receptor targeting proteins Lin-2 and Lin-7.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1958656029  69 MALAEDVMEELQAASVHS-DERELLQLLSTPHLRAVLMVHDTVAQKNFDPVL 119
Cdd:pfam02828   1 VELVLELLEDLQPLSEASeDLAELQKLLQSPHLQALLEAHDKVAQKVYEPPS 52

C-terminal processing protease CtpA/Prc, contains a PDZ domain [Posttranslational modification, protein turnover, chaperones];

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1958656029 147 LGATIRRDEhsGAVVVARIMRGGAADRSGLvHVGDELREVNGITVLHKRPDEISQILAQSQGS-ITLKIIPATQEE 221
Cdd:COG0793    62 LGAELGEED--GKVVVVSVIPGSPAEKAGI-KPGDIILAIDGKSVAGLTLDDAVKLLRGKAGTkVTLTIKRPGEGE 134

L27 domain; The L27 domain is found in receptor targeting proteins Lin-2 and Lin-7.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1958656029  11 HETLALLTSQLRPDSNHREEMGFLRDVFSEKSLGYLMKIHEKLRYYERQSPT 62
Cdd:pfam02828   1 VELVLELLEDLQPLSEASEDLAELQKLLQSPHLQALLEAHDKVAQKVYEPPS 52

Variant SH3 domain; SH3 (Src homology 3) domains are often indicative of a protein involved in signal transduction related to cytoskeletal organization. First described in the Src cytoplasmic tyrosine kinase. The structure is a partly opened beta barrel.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1958656029 230 FMRALFHYDPREdraipcqEAGLPFQQRQVLEVVSQDDPTWWQAKRVGdtnlRAGLIPSKQFQE 293
Cdd:pfam07653   1 YGRVIFDYVGTD-------KNGLTLKKGDVVKVLGKDNDGWWEGETGG----RVGLVPSTAVEE 53

PDZ domain of membrane palmitoylated proteins 3 (MPP3), MPP4, and MPP7, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of MPP3, MPP4, and MPP7, and related domains. MPP3 (also known as MAGUK p55 subfamily member 3, erythrocyte membrane protein p55, or EMP55), MPP4 (also known as MAGUK p55 subfamily member 4 or Discs large homolog 6), and MPP7 (also known as MAGUK p55 subfamily member 7) are membrane-associated guanylate kinase (MAGUK)-like proteins. MPP3 is part of a cell adhesion protein complex including tumor suppressor CADM1 and actin-binding protein 4.1B. Participation in the Crumbs cell polarity complex has also been demonstrated for MPP7 in epithelial cells, and for MPP3 and MPP4 in the retina. MPP4 is needed for proper localization of plasma membrane calcium ATPases and maintenance of calcium homeostasis at the rod photoreceptor synaptic terminals. Binding partners of the MPP3 PDZ domain include nectin-3, serotonin 5-hydroxytryptamine, 5-HT(2C) receptor, and a cell adhesion protein, TSLC1 (tumor suppressor in lung cancer 1); fragments of MPP4 having the PDZ domain bind CRB (PDZ-SH3-GUK) and GABA transporter GAT1 (PDZ-SH3). PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MPP1-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958656029 136 KIVRLVKNKEPLGATIRRDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLKII 215
Cdd:cd06799     1 KIVRLVKNNEPLGATIKRDEKTGAIVVARIMRGGAADRSGLIHVGDELREVNGISVEGKDPEEVIQILANSQGPITFKLI 80

                  .
gi 1958656029 216 P 216
Cdd:cd06799    81 P 81

Src Homology 3 domain of Membrane Protein, Palmitoylated (or MAGUK p55 subfamily member) proteins; The MPP/p55 subfamily of MAGUK (membrane-associated guanylate kinase) proteins includes at least eight vertebrate members (MPP1-7 and CASK), four Drosophila proteins (Stardust, Varicose, CASK and Skiff), and other similar proteins; they all contain one each of the core of three domains characteristic of MAGUK proteins: PDZ, SH3, and guanylate kinase (GuK). In addition, most members except for MPP1 contain N-terminal L27 domains and some also contain a Hook (Protein 4.1 Binding) motif in between the SH3 and GuK domains. CASK has an additional calmodulin-dependent kinase (CaMK)-like domain at the N-terminus. Members of this subfamily are scaffolding proteins that play important roles in regulating and establishing cell polarity, cell adhesion, and synaptic targeting and transmission, among others. The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1958656029 230 FMRALFHYDPREDRAIPCQEAGLPFQQRQVLEVVSQDDPTWWQAKRVGDTNLRAGLIPSKQ 290
Cdd:cd11862     1 FVRALFDYDPEEDPLIPCKEAGLSFKKGDILQIVNQDDPNWWQARKVGDPNGRAGLIPSQD 61

Src Homology 3 domain of Membrane Protein, Palmitoylated 7 (or MAGUK p55 subfamily member 7); MPP7 is a scaffolding protein that binds to DLG1 and promotes tight junction formation and epithelial cell polarity. Mutations in the MPP7 gene may be associated with the pathogenesis of diabetes and extreme bone mineral density. It is one of seven vertebrate homologs of the Drosophila Stardust protein, which is required in establishing cell polarity, and it contains two L27 domains followed by the core of three domains characteristic of MAGUK (membrane-associated guanylate kinase) proteins: PDZ, SH3, and guanylate kinase (GuK). The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1958656029 230 FMRALFHYDPREDRAIPCQEAGLPFQQRQVLEVVSQDDPTWWQAKRVGDTNLRAGLIPSKQ 290
Cdd:cd12033     1 FIKALFDYNPNEDKAIPCKEAGLSFKKGDILQIMSQDDATWWQAKHEGDANPRAGLIPSKH 61

Src Homology 3 domain of Membrane Protein, Palmitoylated 1 (or MAGUK p55 subfamily member 1)-like proteins; This subfamily includes MPP1, CASK (Calcium/calmodulin-dependent Serine protein Kinase), Caenorhabditis elegans lin-2, and similar proteins. MPP1 and CASK are scaffolding proteins from the MAGUK (membrane-associated guanylate kinase) protein family, which is characterized by the presence of a core of three domains: PDZ, SH3, and guanylate kinase (GuK). In addition, they also have the Hook (Protein 4.1 Binding) motif in between the SH3 and GuK domains. The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. CASK and lin-2 also contain an N-terminal calmodulin-dependent kinase (CaMK)-like domain and two L27 domains. MPP1 is ubiquitously-expressed and plays roles in regulating neutrophil polarity, cell shape, hair cell development, and neural development and patterning of the retina. CASK is highly expressed in the mammalian nervous system and plays roles in synaptic protein targeting, neural development, and gene expression regulation. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1958656029 230 FMRALFHYDPREDRAIPCQEAGLPFQQRQVLEVVSQDDPTWWQAKRVGDTNLRAGLIPS 288
Cdd:cd12035     1 YVRAQFDYDPSKDDLIPCQQAGIAFKTGDILQIISKDDHNWWQARKPGASKEPAGLIPS 59

PDZ domain of membrane palmitoylated protein 6 (MPP6), MPP2, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of MPP6, MPP2, and related domains. MPP6 (also known as MAGUK p55 subfamily member, Protein associated with Lin-7, 2 (PALS2), Veli-associated MAGUK 1, and VAM-1) is a membrane-associated guanylate kinase (MAGUK)-like protein. MPP6 is a regulator of Lin-7 expression and localization. MPP6 is also known to bind cell-adhesion protein, nectin-like molecule-2 (Necl-2), and localize to the basolateral plasma membrane in mammalian epithelial cells. MPP2 (also known as MAGUK p55 subfamily member 2) is a postsynaptic protein that links SynCAM1 cell adhesion molecules to core components of the postsynaptic density. Other members of this family include the Drosophila Vari protein, an essential basolateral septate junction protein which interacts with the cell-adhesion protein neurexin IV. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MPP6-MPP2-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958656029 136 KIVRLVKNK-EPLGATIRRDEhsGAVVVARIMRGGAADRSGLVHVGDELREVNGITVlhKRPDEISQILAQSQGSITLKI 214
Cdd:cd10832     1 RMVGIRKNPgEPLGVTVRLEE--GELVIARILHGGMIDRQGLLHVGDIIKEVNGVPV--GSPEQLQEMLKNASGSVTLKI 76

                  ..
gi 1958656029 215 IP 216
Cdd:cd10832    77 LP 78

Src Homology 3 domain of Membrane Protein, Palmitoylated 1 (or MAGUK p55 subfamily member 1); MPP1, also called 55 kDa erythrocyte membrane protein (p55), is a ubiquitously-expressed scaffolding protein that plays roles in regulating neutrophil polarity, cell shape, hair cell development, and neural development and patterning of the retina. It was originally identified as an erythrocyte protein that stabilizes the actin cytoskeleton to the plasma membrane by forming a complex with 4.1R protein and glycophorin C. MPP1 is one of seven vertebrate homologs of the Drosophila Stardust protein, which is required in establishing cell polarity, and it contains the three domains characteristic of MAGUK (membrane-associated guanylate kinase) proteins: PDZ, SH3, and guanylate kinase (GuK). In addition, it also contains the Hook (Protein 4.1 Binding) motif in between the SH3 and GuK domains. The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1958656029 230 FMRALFHYDPREDRAIPCQEAGLPFQQRQVLEVVSQDDPTWWQAKRVGDTNLRAGLIPSKQF 291
Cdd:cd12080     1 YMRAQFDYDPKKDNLIPCKEAGLKFQTGDIIQIINKDDSNWWQGRVEGSGEESAGLIPSPEL 62

Src Homology 3 domain of Calcium/calmodulin-dependent Serine protein Kinase; CASK is a scaffolding protein that is highly expressed in the mammalian nervous system and plays roles in synaptic protein targeting, neural development, and gene expression regulation. CASK interacts with many different binding partners including parkin, neurexin, syndecans, calcium channel proteins, caskin, among others, to perform specific functions in different subcellular locations. Disruption of the CASK gene in mice results in neonatal lethality while mutations in the human gene have been associated with X-linked mental retardation. Drosophila CASK is associated with both pre- and postsynaptic membranes and is crucial in synaptic transmission and vesicle cycling. CASK contains an N-terminal calmodulin-dependent kinase (CaMK)-like domain, two L27 domains, followed by the core of three domains characteristic of MAGUK (membrane-associated guanylate kinase) proteins: PDZ, SH3, and guanylate kinase (GuK). In addition, it also contains the Hook (Protein 4.1 Binding) motif in between the SH3 and GuK domains. The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1958656029 230 FMRALFHYDPREDRAIPCQEAGLPFQQRQVLEVVSQDDPTWWQAKRVGDTNLRAGLIPSKQF 291
Cdd:cd12081     1 YVRAQFEYDPLKDDLIPCKQAGIRFRVGDILQIISKDDHNWWQAKLENSKNGTAGLIPSPEL 62

canonical PDZ domain; Canonical PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain. PDZ domains usually bind to short specific peptide sequences located at the C-terminal end of their partner proteins known as PDZ binding motifs. These domains can also interact with internal peptide motifs and certain lipids, and can take part in a head-to-tail oligomerization with other PDZ domains. The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. The canonical PDZ domain contains six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1958656029 138 VRLVKNK-EPLGATIRR-DEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLKI 214
Cdd:cd00136     2 VTLEKDPgGGLGFSIRGgKDGGGGIFVSRVEPGGPAARDGRLRVGDRILEVNGVSLEGLTHEEAVELLKSAGGEVTLTV 80

Domain present in PSD-95, Dlg, and ZO-1/2; Also called DHR (Dlg homologous region) or GLGF (relatively well conserved tetrapeptide in these domains). Some PDZs have been shown to bind C-terminal polypeptides; others appear to bind internal (non-C-terminal) polypeptides. Different PDZs possess different binding specificities.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958656029  135 VKIVRLVKNKEPLGATIR-RDEHSGAVVVARIMRGGAADRSGLvHVGDELREVNGITVLHKRPDEISQILAQSQGSITLK 213
Cdd:smart00228   2 PRLVELEKGGGGLGFSLVgGKDEGGGVVVSSVVPGSPAAKAGL-RVGDVILEVNGTSVEGLTHLEAVDLLKKAGGKVTLT 80

                   ...
gi 1958656029  214 IIP 216
Cdd:smart00228  81 VLR 83

domain in receptor targeting proteins Lin-2 and Lin-7;

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|..
gi 1958656029   71 LAEDVMEELQAA-SVHSDERELLQLLSTPHLRAVLMVHDTVAQKNFDPVLPP 121
Cdd:smart00569   2 RLLELLEELQSLlSPSEDLQELRRLLQSPHLQALLKIHDKVAETELDPPLPE 53

Src Homology 3 domain of Disks large homolog proteins; The DLG-like proteins are scaffolding proteins that cluster at synapses and are also called PSD (postsynaptic density)-95 proteins or SAPs (synapse-associated proteins). They play important roles in synaptic development and plasticity, cell polarity, migration and proliferation. They are members of the MAGUK (membrane-associated guanylate kinase) protein family, which is characterized by the presence of a core of three domains: PDZ, SH3, and guanylate kinase (GuK). The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. DLG-like proteins contain three PDZ domains and varying N-terminal regions. All DLG proteins exist as alternatively-spliced isoforms. Vertebrates contain four DLG proteins from different genes, called DLG1-4. DLG4 and DLG2 are found predominantly at postsynaptic sites and they mediate surface ion channel and receptor clustering. DLG3 is found axons and some presynaptic terminals. DLG1 interacts with AMPA-type glutamate receptors and is critical in their maturation and delivery to synapses. The SH3 domain of DLG4 binds and clusters the kainate subgroup of glutamate receptors via two proline-rich sequences in their C-terminal tail. It also binds AKAP79/150 (A-kinase anchoring protein). SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1958656029 230 FMRALFHYDPREDRAIPCQeaGLPFQQRQVLEVVSQDDPTWWQAKRVGDTNLRA--GLIPSKQ 290
Cdd:cd11861     1 YVRALFDYDPSRDSGLPSQ--GLSFKFGDILHVTNASDDEWWQARRVTPNGEEEevGVIPSKR 61

PDZ domain of partitioning defective 6 (Par6), Drosophila Rho GTPase-activating protein 100F (RhoGAP100F), and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of Par6 (also known as PAR6 or Par-6), RhoGAP100F, and related domains. Par6 is part of a conserved machinery that directs metazoan cell polarity, a process necessary for the function of diverse cell types. Par6 forms a cell polarity-regulatory complex with atypical protein kinase C (aPKC) and Par3. Par6 can also directly associate with PALS1 (proteins associated with Lin7, also known as Stardust) providing a link between the Par3/aPKC/Par6 complex and the PALS1-PATJ (protein-associated TJ) complex. Binding partners of the Par6-PDZ domain include Par3, PALS1/Stardust; leucine-rich repeat-containing protein netrin-G ligand-2 (NGL-2), human crumbs (CRB3) involve in the morphogenesis of the tight junctions in mammalian epithelial cells, and PAR-6 co-operates with the Par6 semi-CRIB domain to bind CDC42. CDC42 regulates the Par6 PDZ domain through an allosteric CRIB-PDZ transition. Drosophila RhoGAP100F, also known as synapse defective protein 1 homolog (syd-1 homolog), is a GTPase activator for the Rho-type GTPases by converting them to an inactive GDP-bound form. The RhoGAP100F-PDZ domain binds the neurexin C terminus to control synapse formation at the Drosophila neuromuscular junction. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This Par6-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1958656029 136 KIVRLVK-NKEPLGATIRR----DEHSGaVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEI 199
Cdd:cd06718     1 RRVELIKpPGKPLGFYIRDgngvERVPG-IFISRLVLGSLADSTGLLAVGDEILEVNGVEVTGKSLDDV 68

PDZ domain 6 of glutamate receptor-interacting protein 1 (GRIP1) and GRIP2, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) binding proteins GRIP1 (ABP/GRIP2) and GRIP2, and related domains. GRIP1 and GRIP2 each have 7 PDZ domains. The interaction of GRIP1 and GRIP2 with GluA2/3 (AMPAR subunit) regulates AMPAR trafficking and synaptic targeting. GRIP1 has an essential role in regulating AMPAR trafficking during synaptic plasticity and learning and memory. GRIP1 and GRIP2 interact with a variety of other proteins associated with protein trafficking and internalization, for example GRIP1 also interacts with KIF5 (also known as kinesin 1), EphB receptors, scaffold protein liprin-alpha, and the rasGEF GRASP-1. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This GRIP family PDZ6 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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gi 1958656029 138 VRLVKNKEPLGATIR-RDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLKI 214
Cdd:cd06683     6 VELKRYGGPLGITISgTEEPFDPIVISGLTEGGLAERTGAIHVGDRILAINGESLRGKPLSEAIHLLQNAGDTVTLKI 83

Src Homology 3 domain of Disks Large homolog 2; DLG2, also called postsynaptic density-93 (PSD93) or Channel-associated protein of synapse-110 (chapsyn 110), is a scaffolding protein that clusters at synapses and plays an important role in synaptic development and plasticity. The DLG2 delta isoform binds inwardly rectifying potassium Kir2 channels, which determine resting membrane potential in neurons. It regulates the spatial and temporal distribution of Kir2 channels within neuronal membranes. DLG2 is a member of the MAGUK (membrane-associated guanylate kinase) protein family, which is characterized by the presence of a core of three domains: PDZ, SH3, and guanylate kinase (GuK). The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. DLG2 contains three PDZ domains. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1958656029 225 KESKVFMRALFHYDPREDRAIPCQeaGLPFQQRQVLEVVSQDDPTWWQAKRV---GDTNlRAGLIPSKQFQERR 295
Cdd:cd12032     2 QKRSLYVRAMFDYEKSKDSGLPSQ--GLSFRYGDILHVINASDDEWWQARRVtpdGDSE-EMGVIPSKRRVERK 72

C-terminal processing protease CtpA/Prc, contains a PDZ domain [Posttranslational modification, protein turnover, chaperones];

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gi 1958656029 147 LGATIRRDEhsGAVVVARIMRGGAADRSGLvHVGDELREVNGITVLHKRPDEISQILAQSQGS-ITLKIIPATQEE 221
Cdd:COG0793    62 LGAELGEED--GKVVVVSVIPGSPAEKAGI-KPGDIILAIDGKSVAGLTLDDAVKLLRGKAGTkVTLTIKRPGEGE 134

PDZ domain 1 of harmonin isoforms a, b, and c, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 1 of harmonin isoforms a, b, and c, and related domains. Harmonin (also known as Usher Type 1C, PDZ-73 and AIE-75) is a key organizer of the Usher (USH) protein interactome. USH syndrome is the leading cause of hereditary sensory deaf-blindness in humans; three clinically distinct types of USH have been identified, type 1 to 3. The gene encoding harmonin (USH1C) is the causative gene for the USH type 1C phenotype. There are at least 10 alternatively spliced isoforms of harmonin, which are divided into three subclasses (a, b, and c). All isoforms contain the first two PDZ domains and the first coiled-coil domain. The a and b isoforms all have a third PDZ domain. The different PDZ domains are responsible for interactions with all known Usher syndrome type 1 proteins, and most Usher syndrome type 2 proteins. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This harmonin family PDZ1 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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gi 1958656029 135 VKIVRLVKN-KEPLGATIRRD-EHSGAVVVARIMRGGAADRSGLvHVGDELREVNGITVLHKRPDEISQiLAQSQGSITL 212
Cdd:cd06737     2 LRLVRLDRRgPESLGFSVRGGlEHGCGLFVSHVSPGSQADNKGL-RVGDEIVRINGYSISQCTHEEVIN-LIKTKKTVSL 79

                  ..
gi 1958656029 213 KI 214
Cdd:cd06737    80 KV 81

PDZ domain of syntrophins, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of syntrophins (including alpha-1-syntrophin, beta-1-syntrophin, beta-2-syntrophin, gamma-1-syntrophin, and gamma-2-syntrophin), and related domains. Syntrophins play a role in recruiting various signaling molecules into signaling complexes and help provide appropriate spatiotemporal regulation of signaling pathways. They function in cytoskeletal organization and maintenance; as components of the dystrophin-glycoprotein complex (DGC), they help maintain structural integrity of skeletal muscle fibers. They link voltage-gated sodium channels to the actin cytoskeleton and the extracellular matrix, and control the localization and activity of the actin reorganizing proteins such as PI3K, PI(3,4)P2 and TAPP1. Through association with various cytoskeletal proteins within the cells, they are involved in processes such as regulation of focal adhesions, myogenesis, calcium homeostasis, and cell migration. They also have roles in synapse formation and in the organization of utrophin, acetylcholine receptor, and acetylcholinesterase at the neuromuscular synapse. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This syntrophin-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958656029 136 KIVRLVKNKEP-LGATIRR-DEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLK 213
Cdd:cd06801     1 RTVRVVKQDVGgLGISIKGgAEHKMPILISKIFKGQAADQTGQLFVGDAILSVNGENLEDATHDEAVQALKNAGDEVTLT 80

                  .
gi 1958656029 214 I 214
Cdd:cd06801    81 V 81

L27 domain; The L27 domain is found in receptor targeting proteins Lin-2 and Lin-7.

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gi 1958656029  11 HETLALLTSQLRPDSNHREEMGFLRDVFSEKSLGYLMKIHEKLRYYERQSPT 62
Cdd:pfam02828   1 VELVLELLEDLQPLSEASEDLAELQKLLQSPHLQALLEAHDKVAQKVYEPPS 52

Src homology 3 domains; Src homology 3 (SH3) domains bind to target proteins through sequences containing proline and hydrophobic amino acids. Pro-containing polypeptides may bind to SH3 domains in 2 different binding orientations.

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                   ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1958656029  227 SKVFMRALFHYDPREDraipcQEagLPFQQRQVLEVVSQDDPTWWQAKRVgdtNLRAGLIPS 288
Cdd:smart00326   1 EGPQVRALYDYTAQDP-----DE--LSFKKGDIITVLEKSDDGWWKGRLG---RGKEGLFPS 52

PDZ domain 3 of harmonin isoforms a and b, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 3 of harmonin isoforms a and b, and related domains. Harmonin (also known as Usher Type 1C, PDZ-73 and AIE-75) is a key organizer of the Usher (USH) protein interactome. USH syndrome is the leading cause of hereditary sensory deaf-blindness in humans; three clinically distinct types of USH have been identified, type 1 to 3. The gene encoding harmonin (USH1C) is the causative gene for the USH type 1C phenotype. There are at least 10 alternatively spliced isoforms of harmonin, which are divided into three subclasses (a, b, and c). All isoforms contain the first two PDZ domains and the first coiled-coil domain. The a and b isoforms all have a third PDZ domain. The different PDZ domains are responsible for interactions with all known Usher syndrome type 1 proteins, and most Usher syndrome type 2 proteins. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This harmonin family PDZ3 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1958656029 135 VKIVRLVKNKePLGATIR---RDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGS 209
Cdd:cd06739     3 VRLLRIKKNG-PLDLALEggiDSPLGGKIVVSAVYEGGAADKHGGIVKGDQIMMVNGKSLTDVTLAEAEAALQRAMNS 79

PDZ domain 2 of Drosophila Scribble, human Scribble homolog, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 2 of Drosophila Scribble (also known as LAP4), human Scribble homolog (also known as hScrib, LAP4, CriB1, ScrB1 and Vartul), and related domains. They belong to the LAP family, which describes proteins that contain either one or four PDZ domains and 16 LRRs (leucine-rich repeats) and function in controlling cell shape, size and subcellular protein localization. In Drosophila, the Scribble complex, comprising Scribble, discs large, and lethal giant larvae, plays a role in apico-basal cell polarity, in other forms of polarity, including regulation of the actin cytoskeleton, cell signaling and vesicular trafficking, and in tumor development. Mammalian Scribble is important in many aspects of cancer development. Scribble and its homologs can be downregulated or overexpressed in cancer; they have a role in cancer beyond their function in loss of cell polarity. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This Scribble-like family PDZ2 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1958656029 148 GATIRRDEHSGaVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITL 212
Cdd:cd06703    23 GSTPFRDGDEG-IFISRITEGGAADRDGKLQVGDRVLSINGVDVTEARHDQAVALLTSSSPTITL 86

PDZ domain 8 of multi-PDZ-domain protein 1 (MUPP1), PDZ domain 7 of protein-associated tight junction (PATJ), PDZ domain 2 of Drosophila melanogaster inactivation-no-after-potential D (INAD), and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 8 of MUPP1, PDZ domain 7 of PATJ, and PDZ domain 2 of Drosophila melanogaster INAD, and related domains. MUPP1 and PATJ serve as scaffolding proteins linking different proteins and protein complexes involved in the organization of tight junctions and epithelial polarity. MUPP1 contains an L27 (Lin-2 and Lin-7 binding) domain and 13 PDZ domains. PATJ (also known as INAD-like) contains an L27 domain and ten PDZ domains. MUPP1 and PATJ share several binding partners, including junctional adhesion molecules (JAM), zonula occludens (ZO)-3, Pals1 (protein associated with Lin-7), Par (partitioning defective)-6 proteins, and nectins (adherence junction adhesion molecules). PATJ lacks 3 PDZ domains seen in MUPP1: PDZ6, 9, and 13; consequently, MUPP1 PDZ7 and 8 align with PATJ PDZ6 and 7; and MUPP1 PDZ domains 10-12 align with PATJ PDZ domains 8-10. INAD assembles key enzymes of the Drosophila compound eye photo-transduction pathway into a supramolecular complex, supporting efficient and fast light signaling. It contains 5 PDZ domains arranged in tandem (PDZ1-PDZ5) which independently bind various proteins. INAD PDZ2 binds eye-specific protein kinase C. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MUPP1-like family PDZ8 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1958656029 137 IVRLVKNKEPLGATI--RRDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGItVLHKR 195
Cdd:cd06672     3 LIELEKGSSGLGLSLagNKDRSRMSVFVVGIDPDGAAGKDGRIQVGDELLEINGQ-VLYGR 62

Src Homology 3 domain of Disks Large homolog 4; DLG4, also called postsynaptic density-95 (PSD95) or synapse-associated protein 90 (SAP90), is a scaffolding protein that clusters at synapses and plays an important role in synaptic development and plasticity. It is responsible for the membrane clustering and retention of many transporters and receptors such as potassium channels and PMCA4b, a P-type ion transport ATPase, among others. DLG4 is a member of the MAGUK (membrane-associated guanylate kinase) protein family, which is characterized by the presence of a core of three domains: PDZ, SH3, and guanylate kinase (GuK). The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. DLG4 contains three PDZ domains. The SH3 domain of DLG4 binds and clusters the kainate subgroup of glutamate receptors via two proline-rich sequences in their C-terminal tail. It also binds AKAP79/150 (A-kinase anchoring protein). SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1958656029 230 FMRALFHYDPREDRAIPCQeaGLPFQQRQVLEVVSQDDPTWWQAKRV---GDTNlRAGLIPSKQ 290
Cdd:cd12030     3 YIRALFDYDKTKDCGFLSQ--ALSFRFGDVLHVIDAGDEEWWQARRVhsdSETE-EIGFIPSKR 63

PDZ domain 3 of human discs large homolog 1 (Dlg1), Dlg2, and Dlg4, Drosophila disc large (Dlg), and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 3 of Drosophila Dlg1, human Dlg1, 2, and 4 and related domains. Dlg1 (also known as synapse-associated protein Dlg197; SAP-97), Dlg2 (also known as channel-associated protein of synapse-110; postsynaptic density protein 93, PSD-93), Dlg4 (also known as postsynaptic density protein 95, PSD-95; synapse-associated protein 90, SAP-90) each have 3 PDZ domains and belong to the membrane-associated guanylate kinase family. Dlg1 regulates antigen receptor signaling and cell polarity in lymphocytes, B-cell proliferation and antibody production, and TGFalpha bioavailability; its PDZ3 domain binds pro-TGFalpha, and its PDZ2 domain binds the TACE metalloprotease responsible for cleaving pro-TGFalpha to a soluble form. Dlg2 is involved in N-methyl-D-aspartate (NMDA) receptor signaling, regulating surface expression of NMDA receptors in dorsal horn neurons of the spinal cord; it interacts with NMDA receptor subunits and with Shaker-type K+ channel subunits to cluster into a channel complex. The Dlg4 PDZ1 domain binds NMDA receptors, and its PDZ2 domain binds neuronal nitric oxide synthase (nNOS), forming a complex in neurons. The Drosophila Scribble complex (Scribble, Dlg, and lethal giant larvae) plays a role in apico-basal cell polarity, and in other forms of polarity, including regulation of the actin cytoskeleton, cell signaling and vesicular trafficking, and in tumor development; postsynaptic targeting of Drosophila DLG requires interactions mediated by the first two PDZ domains. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This Dlg-like family PDZ3 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958656029 136 KIVRLVKNKEPLGATIRRDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLKII 215
Cdd:cd06795     3 RKIVLHKGSTGLGFNIVGGEDGEGIFISFILAGGPADLSGELRRGDQILSVNGVDLRNATHEQAAAALKNAGQTVTIIAQ 82

                  ....*....
gi 1958656029 216 PATQEEDRF 224
Cdd:cd06795    83 YKPEEYSRF 91

PDZ domain 2 of multi-PDZ-domain protein 1 (MUPP1) and PATJ (protein-associated tight junction) and similar domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 2 of MUPP1 and PATJ, and related domains. MUPP1 and PATJ serve as scaffolding proteins linking different proteins and protein complexes involved in the organization of tight junctions and epithelial polarity. MUPP1 contains an L27 (Lin-2 and Lin-7 binding) domain and 13 PDZ domains. PATJ (also known as INAD-like) contains an L27 domain and ten PDZ domains. MUPP1 and PATJ share several binding partners, including junctional adhesion molecules (JAM), zonula occludens (ZO)-3, Pals1 (protein associated with Lin-7), Par (partitioning defective)-6 proteins, and nectins (adherence junction adhesion molecules). PATJ lacks 3 PDZ domains seen in MUPP1: PDZ6, 9, and 13; consequently, MUPP1 PDZ7 and 8 align with PATJ PDZ6 and 7; and MUPP1 PDZ domains 10-12 align with PATJ PDZ domains 8-10. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MUPP1-like family PDZ2 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F

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                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1958656029 156 HSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLKI 214
Cdd:cd06667    20 KSTGVVVKTILPGGVADRDGRLRSGDHILQIGDTNLRGMGSEQVAQVLRQCGSHVRLVV 78

PDZ domain 4 of glutamate receptor-interacting protein 1 (GRIP1) and GRIP2, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) binding proteins GRIP1 (ABP/GRIP2) and GRIP2, and related domains. GRIP1 and GRIP2 each have 7 PDZ domains. The interaction of GRIP1 and GRIP2 with GluA2/3 (AMPAR subunit) regulates AMPAR trafficking and synaptic targeting. GRIP1 has an essential role in regulating AMPAR trafficking during synaptic plasticity and learning and memory. GRIP1 and GRIP2 interact with a variety of other proteins associated with protein trafficking and internalization, for example GRIP1 also interacts with KIF5 (also known as kinesin 1), EphB receptors, scaffold protein liprin-alpha, and the rasGEF GRASP-1. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This GRIP family PDZ4 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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                  ....*....|....*....|....*....|....*....|....*....|....
gi 1958656029 161 VVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITLKI 214
Cdd:cd06686    39 LISFIEPDSPAERCGVLQVGDRVLSINGIPTEDRTLEEANQLLRDSASKVTLEI 92

PDZ domain 4 of Drosophila Scribble, human Scribble homolog, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 4 of Drosophila Scribble (also known as LAP4), human Scribble homolog (also known as hScrib, LAP4, CriB1, ScrB1 and Vartul), and related domains. They belong to the LAP family, which describes proteins that contain either one or four PDZ domains and 16 LRRs (leucine-rich repeats) and function in controlling cell shape, size and subcellular protein localization. In Drosophila, the Scribble complex, comprising Scribble, discs large, and lethal giant larvae, plays a role in apico-basal cell polarity, in other forms of polarity, including regulation of the actin cytoskeleton, cell signaling and vesicular trafficking, and in tumor development. Mammalian Scribble is important in many aspects of cancer development. Scribble and its homologs can be downregulated or overexpressed in cancer; they have a role in cancer beyond their function in loss of cell polarity. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This Scribble-like family PDZ4 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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gi 1958656029 138 VRLVKNK-EPLGATIR----------RDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQS 206
Cdd:cd06701     7 LTIVKEPgEKLGISIRggakghagnpLDPTDEGIFISKINPDGAAARDGRLKVGQRILEVNGQSLLGATHQEAVRILRSV 86

                  ....*.
gi 1958656029 207 QGSITL 212
Cdd:cd06701    87 GDTLTL 92

PDZ domain of neuronal nitric oxide synthase (nNOS), and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 1 of nNOS, and related domains. nNOS produces a key signaling molecule, nitric oxide (NO), which has diverse functions throughout the body and acts as a neurotransmitter and intracellular signaling molecule in the central and peripheral nervous system. nNOS is concentrated at synaptic junctions in the brain and motor endplates in skeletal muscle. The PDZ domain of neuronal nitric oxide synthase (nNOS) interacts with the PDZ domain of alpha1-syntrophin (in muscle cells) and with the second PDZ domain of Disks large homolog 4 (Dlg4, also known as PSD-95), and nitric oxide synthase 1 adaptor protein NOS1AP in neurons. Dlg4 binds NMDA receptors, and nNOS, forming a complex in neurons. NOS1AP competes with Dgl4 for the nNOS PDZ domain and prevents the coupling of nNos activation with NMDA receptor-mediated calcium influx. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This nNOS-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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gi 1958656029 138 VRLVKNKEP-LGATIRRDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGI 189
Cdd:cd06708     5 VRLFKRKVGgLGFLVKQRVCKPPVIISDLIRGGAAEQSGLVQVGDIILAVNGR 57

PDZ domain of afadin (AFDN), and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of afadin (AFDN, also known as ALL1-fused gene from chromosome 6 protein (AF6) and MLLT4), and related domains. AFDN belongs to the adhesion system, probably together with the E-cadherin-catenin system, that plays a role in the organization of homotypic, interneuronal, and heterotypic cell-cell adherens junctions. The AFDN PDZ domain interaction partners include poliovirus receptor-related protein PRR2/nectin, the junctional adhesion molecule (JAM), the breakpoint-cluster-region protein (BCR), connexin36 (Cx36), and a subset of Eph-related receptor tyrosine kinases; it can also bind low molecular weight ligands, in competition with a natural peptide ligand. Other AFDN-binding proteins have been identified. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This AFDN family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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gi 1958656029 138 VRLVKNKEPLGATI-----RRDEHSGaVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQILAQSQGSITL 212
Cdd:cd06789     6 VTLKKVGNGMGLSIvaakgAGQDKLG-IYIKSVVKGGAADLDGRLQAGDQLLSVDGHSLVGLSQERAAELMTKTGSVVTL 84

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gi 1958656029 213 KII 215
Cdd:cd06789    85 EVA 87

PDZ domain 2 of partitioning defective 3 (Par3), and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 2 of Par3 (or PAR3 or Par-3, also known as Atypical PKC isotype-specific-interacting protein, ASIP, Drosophila Bazooka) and related domains. Par3 is a scaffold protein involved in organizing cell polarity across animals. Par3 binds numerous molecules both for its recruitment to one pole of the cell and for downstream contributions to polarized cell function. It regulates cell polarity by targeting the Par complex proteins Par6 and atypical protein kinase C (aPKC) to specific cortical sites. Physical interactions between Par3 and the Par complex include Par3 PDZ domain 1 binding to the Par6 PDZ domain, Par3 PDZ domain 1 and PDZ domain 3 binding the Par6's PDZ-binding motif, and an interaction with an undefined region of aPKC that requires both Par3 PDZ2 and PDZ3. The PDZ domains of Par3 have also been implicated as potential phosphoinositide signaling integrators, since its second PDZ domain binds to phosphoinositides, and the third PDZ interacts with phosphoinositide phosphatase PTEN. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This Par3 family PDZ2 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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gi 1958656029 138 VRLVKNKEPLGATI-RRD---EHSGAVVVARIMRGGAADRSGLVHVGDELREVNGITVLHKRPDEISQIL 203
Cdd:cd23058     8 IQLKKGPEGLGFSItSRDnptGGSGPIYIKNILPKGAAIQDGRLKAGDRLLEVNGVDVTGKTQEEVVSLL 77

PDZ domain 6 of multi-PDZ-domain protein 1 (MUPP1) and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 6 of multi-PDZ-domain protein 1 (MUPP1). MUPP1 and PATJ serve as scaffolding proteins linking different proteins and protein complexes involved in the organization of tight junctions and epithelial polarity. MUPP1 contains an L27 (Lin-2 and Lin-7 binding) domain and 13 PDZ domains. PATJ (also known as INAD-like) contains an L27 domain and ten PDZ domains. PATJ lacks 3 PDZ domains seen in MUPP1: PDZ6, PDZ9, and PDZ13. This MuPP1-like PDZ6 domain is therefore absent from PATJ. MUPP1 and PATJ share several binding partners, including junctional adhesion molecules (JAM), zonula occludens (ZO)-3, Pals1 (protein associated with Lin-7), Par (partitioning defective)-6 proteins, and nectins (adherence junction adhesion molecules). PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MUPP1-like family PDZ6 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F

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gi 1958656029 135 VKIVRLVKNKEPLGATIRRDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNG 188
Cdd:cd06670     4 ERTITIVKGNSSLGITVSADKDGNGCIVKSIIHGGAVSRDGRISVGDFIVSINN 57

Src Homology 3 domain superfamily; Src Homology 3 (SH3) domains are protein interaction domains that bind proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. Thus, they are referred to as proline-recognition domains (PRDs). SH3 domains are less selective and show more diverse specificity compared to other PRDs. They have been shown to bind peptide sequences that lack the PxxP motif; examples include the PxxDY motif of Eps8 and the RKxxYxxY sequence in SKAP55. SH3 domain containing proteins play versatile and diverse roles in the cell, including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies, among others. Many members of this superfamily are adaptor proteins that associate with a number of protein partners, facilitating complex formation and signal transduction.

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gi 1958656029 230 FMRALFHYDPREDRAipcqeagLPFQQRQVLEVVSQDDPTWWQAKRVGDtnlRAGLIPS 288
Cdd:cd00174     1 YARALYDYEAQDDDE-------LSFKKGDIITVLEKDDDGWWEGELNGG---REGLFPA 49

PDZ domain 5 of membrane-associated guanylate kinase inverted 1 (MAGI-1), MAGI-2, and MAGI-3, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 5 of MAGI1, 2, 3 (MAGI is also known as Membrane-associated guanylate kinase, WW and PDZ domain-containing protein) and related domains. MAGI proteins have been implicated in the control of cell migration and invasion through altering the activity of phosphatase and tensin homolog (PTEN) and modulating Akt signaling. Four MAGI proteins have been identified (MAGI1-3 and MAGIX). MAGI1-3 have 6 PDZ domains and bind to the C-terminus of PTEN via their PDZ2 domain. MAGIX has a single PDZ domain that is related to MAGI1-3 PDZ domain 5, and belongs to this MAGI1,2,3-like family. Other binding partners for MAGI1 include JAM4, C-terminal tail of high risk HPV-18 E6, megalin, TRAF6, Kir4.1 (basolateral K+ channel subunit), and cadherin 23; for MAGI2, include DASM1, dendrin, axin, beta- and delta-catenin, neuroligin, hyperpolarization-activated cation channels, beta1-adrenergic receptors, NMDA receptor, and TARPs; and for MAGI3 includes LPA2. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MAGI family PDZ5 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged as beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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gi 1958656029 138 VRLVKNKEPLGATIR--RDEHSGAVVVARIMRGGAADRSGLVHVGDELREVNGI 189
Cdd:cd06735     4 VELERGPKGFGFSIRggREYNNMPLYVLRLAEDGPAQRDGRLRVGDQILEINGE 57