Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526 105 LILQAP-LSVFEGDSVVLRCRAKAEVTLNNTIY-KNDNVLAFLNKRTDFHIPHACLKDNGAYRCTGYKEScCPVSSNTVK 182
Cdd:cd05753    2 LLLQAPsAVVFEGEPLTLRCHGWKDKKVHKVTYyKDGKALKFSYENSNFSIPQATLSDSGSYHCSGTVRI-KRRSSESVN 80

                 ...
gi 157694526 183 IQV 185
Cdd:cd05753   81 ITV 83

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 157694526  565 RPILTLRVPRAQAVVGDLLELHCEAPRGSPPILYWfYHEDVTLGSSSAPSGGEASFNLSL-----TAEHSGNYSCEANN 638
Cdd:pfam13927   1 KPVITVSPSSVTVREGETVTLTCEATGSPPPTITW-YKNGEPISSGSTRSRSLSGSNSTLtisnvTRSDAGTYTCVASN 78

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526  754 LTLRAPGTHAAVGDLLELHCEALrGSPLILYRFFHEDVTLgnrssPSGGASLNLSLTAEHSGNYSCEADNGLGAQRSETV 833
Cdd:pfam13895   2 PVLTPSPTVVTEGEPVTLTCSAP-GNPPPSYTWYKDGSAI-----SSSPNFFTLSVSAEDSGTYTCVARNGRGGKVSNPV 75

                  ..
gi 157694526  834 TL 835
Cdd:pfam13895  76 EL 77

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 157694526  658 RPILTFRAPRAQAVVGDLLELHCEALRGSSPILYWfYHEDVTLGKISAPSGGGASFNLSL-----TTEHSGIYSCEADN 731
Cdd:pfam13927   1 KPVITVSPSSVTVREGETVTLTCEATGSPPPTITW-YKNGEPISSGSTRSRSLSGSNSTLtisnvTRSDAGTYTCVASN 78

Second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs). Interactions between IgG and FcgammaR are important to the initiation of cellular and humoral response. IgG binding to FcgammaR leads to a cascade of signals and ultimately to functions such as antibody-dependent-cellular-cytotoxicity (ADCC), endocytosis, phagocytosis, release of inflammatory mediators, etc. FcgammaR has two Ig-like domains. This group also contains FcepsilonRI which binds IgE with high affinity.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526 105 LILQAP-LSVFEGDSVVLRCRAKAEVTLNNTIY-KNDNVLAFLNKRTDFHIPHACLKDNGAYRCTGYKEScCPVSSNTVK 182
Cdd:cd05753    2 LLLQAPsAVVFEGEPLTLRCHGWKDKKVHKVTYyKDGKALKFSYENSNFSIPQATLSDSGSYHCSGTVRI-KRRSSESVN 80

                 ...
gi 157694526 183 IQV 185
Cdd:cd05753   81 ITV 83

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 157694526  565 RPILTLRVPRAQAVVGDLLELHCEAPRGSPPILYWfYHEDVTLGSSSAPSGGEASFNLSL-----TAEHSGNYSCEANN 638
Cdd:pfam13927   1 KPVITVSPSSVTVREGETVTLTCEATGSPPPTITW-YKNGEPISSGSTRSRSLSGSNSTLtisnvTRSDAGTYTCVASN 78

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526  754 LTLRAPGTHAAVGDLLELHCEALrGSPLILYRFFHEDVTLgnrssPSGGASLNLSLTAEHSGNYSCEADNGLGAQRSETV 833
Cdd:pfam13895   2 PVLTPSPTVVTEGEPVTLTCSAP-GNPPPSYTWYKDGSAI-----SSSPNFFTLSVSAEDSGTYTCVARNGRGGKVSNPV 75

                  ..
gi 157694526  834 TL 835
Cdd:pfam13895  76 EL 77

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 157694526  658 RPILTFRAPRAQAVVGDLLELHCEALRGSSPILYWfYHEDVTLGKISAPSGGGASFNLSL-----TTEHSGIYSCEADN 731
Cdd:pfam13927   1 KPVITVSPSSVTVREGETVTLTCEATGSPPPTITW-YKNGEPISSGSTRSRSLSGSNSTLtisnvTRSDAGTYTCVASN 78

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526   577 AVVGDLLELHCEAPRGSPPILYWFYHEDVTLGSSS----APSGGEASFNLS-LTAEHSGNYSCEANNGLVaQHSDTISLS 651
Cdd:smart00410   6 VKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGrfsvSRSGSTSTLTISnVTPEDSGTYTCAATNSSG-SASSGTTLT 84

                   .
gi 157694526   652 V 652
Cdd:smart00410  85 V 85

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 157694526 490 VTLHCEVqRGSPQILYQFYHEDMPLWSSSTPSVGRVSFSFSLT-----EGHSGNYYCTADNGFGPQRSEVV 555
Cdd:cd00096    1 VTLTCSA-SGNPPPTITWYKNGKPLPPSSRDSRRSELGNGTLTisnvtLEDSGTYTCVASNSAGGSASASV 70

First immunoglobulin (Ig) domain of contactin; member of the I-set of (Ig) superfamily domains; The members here are composed of the first immunoglobulin (Ig) domain of contactins. Contactins are neural cell adhesion molecules and are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. The first four Ig domains form the intermolecular binding fragment, which arranges as a compact U-shaped module via contacts between Ig domains 1 and 4, and between Ig domains 2 and 3. Contactin-2 (TAG-1, axonin-1) may play a part in the neuronal processes of neurite outgrowth, axon guidance and fasciculation, and neuronal migration. This group also includes contactin-1 and contactin-5. The different contactins show different expression patterns in the central nervous system. During development and in adulthood, contactin-2 is transiently expressed in subsets of central and peripheral neurons. Contactin-5 is expressed specifically in the rat postnatal nervous system, peaking at about 3 weeks postnatal, and a lack of contactin-5 (NB-2) results in an impairment of neuronal activity in the rat auditory system. Contactin-5 is highly expressed in the adult human brain in the occipital lobe and in the amygdala. Contactin-1 is differentially expressed in tumor tissues and may, through a RhoA mechanism, facilitate invasion and metastasis of human lung adenocarcinoma. This group belongs to the I-set of IgSF domains.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526 387 PEDLIF-EGA---KVTLHCEAqRGSLPILYQFHHEGAALE----RRSANSAGGVAISFSLTAEHSGNYYCTADNGFGPQR 458
Cdd:cd04967    8 PDDTIFpEDSdekKVALNCRA-RANPVPSYRWLMNGTEIDlesdYRYSLVDGTLVISNPSKAKDAGHYQCLATNTVGSVL 86

                 ....*..
gi 157694526 459 SKAVSLS 465
Cdd:cd04967   87 SREATLQ 93

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 157694526 769 LELHCEAlRGSPLILYRFFHEDVTLGN-----RSSPSGGASLNLS-LTAEHSGNYSCEADNGLGAQRSETV 833
Cdd:cd00096    1 VTLTCSA-SGNPPPTITWYKNGKPLPPssrdsRRSELGNGTLTISnVTLEDSGTYTCVASNSAGGSASASV 70

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526   759 PGTHAAVGDLLELHCEAlRGSP---LILYRFFHEDVTLGNR---SSPSGGASLNLS-LTAEHSGNYSCEADNGLGaQRSE 831
Cdd:smart00410   2 PSVTVKEGESVTLSCEA-SGSPppeVTWYKQGGKLLAESGRfsvSRSGSTSTLTISnVTPEDSGTYTCAATNSSG-SASS 79

                   ....*.
gi 157694526   832 TVTLYI 837
Cdd:smart00410  80 GTTLTV 85

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526   110 PLSVFEGDSVVLRCRAKAEVTLNNTIYKNDNVLAFLNKRTD---------FHIPHACLKDNGAYRCTGYKESccPVSSNT 180
Cdd:smart00410   3 SVTVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGRFSvsrsgststLTISNVTPEDSGTYTCAATNSS--GSASSG 80

                   ....*
gi 157694526   181 VKIQV 185
Cdd:smart00410  81 TTLTV 85

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526   393 EGAKVTLHCEAQrGSLPILYQFHHEGAAL----ERRSANSAGGVA---ISfSLTAEHSGNYYCTADNGFGpQRSKAVSLS 465
Cdd:smart00410   8 EGESVTLSCEAS-GSPPPEVTWYKQGGKLlaesGRFSVSRSGSTStltIS-NVTPEDSGTYTCAATNSSG-SASSGTTLT 84

                   .
gi 157694526   466 V 466
Cdd:smart00410  85 V 85

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 157694526   300 EGTKVTLHCETQEDSLRTLYRFYHEGVPL----RHKSVRCERGASISFS-LTTENSGNYYCTADNGLGAKpSKAVSLSV 373
Cdd:smart00410   8 EGESVTLSCEASGSPPPEVTWYKQGGKLLaesgRFSVSRSGSTSTLTISnVTPEDSGTYTCAATNSSGSA-SSGTTLTV 85

Second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs). Interactions between IgG and FcgammaR are important to the initiation of cellular and humoral response. IgG binding to FcgammaR leads to a cascade of signals and ultimately to functions such as antibody-dependent-cellular-cytotoxicity (ADCC), endocytosis, phagocytosis, release of inflammatory mediators, etc. FcgammaR has two Ig-like domains. This group also contains FcepsilonRI which binds IgE with high affinity.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526 105 LILQAP-LSVFEGDSVVLRCRAKAEVTLNNTIY-KNDNVLAFLNKRTDFHIPHACLKDNGAYRCTGYKEScCPVSSNTVK 182
Cdd:cd05753    2 LLLQAPsAVVFEGEPLTLRCHGWKDKKVHKVTYyKDGKALKFSYENSNFSIPQATLSDSGSYHCSGTVRI-KRRSSESVN 80

                 ...
gi 157694526 183 IQV 185
Cdd:cd05753   81 ITV 83

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526  473 PVLTLSSAEalTFEGATVTLHCEVQrGSPQILYQFYHEDMPLWSSSTpsvgrvSFSFSLTEGHSGNYYCTADNGFGPQRS 552
Cdd:pfam13895   2 PVLTPSPTV--VTEGEPVTLTCSAP-GNPPPSYTWYKDGSAISSSPN------FFTLSVSAEDSGTYTCVARNGRGGKVS 72

                  ....*..
gi 157694526  553 EVVSLFV 559
Cdd:pfam13895  73 NPVELTV 79

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526  380 PVLNLSSPEdlIFEGAKVTLHCEAQrGSLPILYQFHHEGAALerrsanSAGGVAISFSLTAEHSGNYYCTADNGFGPQRS 459
Cdd:pfam13895   2 PVLTPSPTV--VTEGEPVTLTCSAP-GNPPPSYTWYKDGSAI------SSSPNFFTLSVSAEDSGTYTCVARNGRGGKVS 72

                  ....*..
gi 157694526  460 KAVSLSV 466
Cdd:pfam13895  73 NPVELTV 79

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526  287 PVLTLSPEKAlnFEGTKVTLHCETQEDSLrTLYRFYHEGVPLRhksvrcERGASISFSLTTENSGNYYCTADNGLGAKPS 366
Cdd:pfam13895   2 PVLTPSPTVV--TEGEPVTLTCSAPGNPP-PSYTWYKDGSAIS------SSPNFFTLSVSAEDSGTYTCVARNGRGGKVS 72

                  ....*..
gi 157694526  367 KAVSLSV 373
Cdd:pfam13895  73 NPVELTV 79

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 157694526  287 PVLTLSPEKALNFEGTKVTLHCETQEDSLRTlYRFYHEGVPLRHKSVRCERGASISFSL-----TTENSGNYYCTADN 359
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGSPPPT-ITWYKNGEPISSGSTRSRSLSGSNSTLtisnvTRSDAGTYTCVASN 78

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 157694526  380 PVLNLSSPEDLIFEGAKVTLHCEAQRGSLPIlYQFHHEGAALERRSANSAGGVAISFSL-----TAEHSGNYYCTADN 452
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGSPPPT-ITWYKNGEPISSGSTRSRSLSGSNSTLtisnvTRSDAGTYTCVASN 78

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526  105 LILQAPLS-VFEGDSVVLRCRAKAEVTLNNTIYKNDNVlafLNKRTDFHIPHACLKDNGAYRCT-GYKESCCPvsSNTVK 182
Cdd:pfam13895   2 PVLTPSPTvVTEGEPVTLTCSAPGNPPPSYTWYKDGSA---ISSSPNFFTLSVSAEDSGTYTCVaRNGRGGKV--SNPVE 76

                  ...
gi 157694526  183 IQV 185
Cdd:pfam13895  77 LTV 79

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 157694526 583 LELHCEAPRGSPPILYWfYHEDVTLGSSSAPSGGEASFNLSLT-----AEHSGNYSCEANNGLVAQHSDTI 648
Cdd:cd00096    1 VTLTCSASGNPPPTITW-YKNGKPLPPSSRDSRRSELGNGTLTisnvtLEDSGTYTCVASNSAGGSASASV 70

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526   486 EGATVTLHCEVQrGSPQILYQFYHEDM-PLWSSSTPSVGRVSFSFSLT-----EGHSGNYYCTADNGFGPQRSEVvslFV 559
Cdd:smart00410   8 EGESVTLSCEAS-GSPPPEVTWYKQGGkLLAESGRFSVSRSGSTSTLTisnvtPEDSGTYTCAATNSSGSASSGT---TL 83

                   ..
gi 157694526   560 TV 561
Cdd:smart00410  84 TV 85

Second Ig-like domain of Junctional adhesion molecule-1 (JAM1); a member of the I-set of IgSF domains; The members here are composed of the second Ig-like domain of Junctional adhesion molecule-1 (JAM1). JAM1 is an immunoglobulin superfamily (IgSF) protein with two Ig-like domains in its extracellular region; it plays a role in the formation of endothelial and epithelial tight junction and acts as a receptor for mammalian reovirus sigma-1. The IgSF is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. The two sheets are linked together by a conserved disulfide bond between B strand and F strand. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The second Ig-like domain of JAM1 is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, the A strand of the I-set is discontinuous but lacks a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526 380 PVLNLSSPEDLifeGAKVTLHCEAQRGSLPILYQFHHEGAALERRSANSAGGVAISFSL------------TAEHSGNYY 447
Cdd:cd20950    1 PTVNIPSSATI---GNRAVLTCSEPDGSPPSEYTWFKDGVVMPTNPKSTRAFSNSSYSLdpttgelvfdplSASDTGEYS 77

                         90       100
                 ....*....|....*....|
gi 157694526 448 CTADNGFG-PQRSKAVSLSV 466
Cdd:cd20950   78 CEARNGYGtPMRSNAVRMEA 97

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 157694526 769 LELHCEAlRGSPLILYRFFHEDVTLGN-----RSSPSGGASLNLS-LTAEHSGNYSCEADNGLGAQRSETV 833
Cdd:cd00096    1 VTLTCSA-SGNPPPTITWYKNGKPLPPssrdsRRSELGNGTLTISnVTLEDSGTYTCVASNSAGGSASASV 70

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 157694526   759 PGTHAAVGDLLELHCEAlRGSP---LILYRFFHEDVTLGNR---SSPSGGASLNLS-LTAEHSGNYSCEADNGLGaQRSE 831
Cdd:smart00410   2 PSVTVKEGESVTLSCEA-SGSPppeVTWYKQGGKLLAESGRfsvSRSGSTSTLTISnVTPEDSGTYTCAATNSSG-SASS 79

                   ....*.
gi 157694526   832 TVTLYI 837
Cdd:smart00410  80 GTTLTV 85

Immunoglobulin (Ig)-like domain in neuregulins; The members here are composed of the immunoglobulin (Ig)-like domain in neuregulins (NRGs). NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. There are four members of the neuregulin gene family (NRG-1, NRG-2, NRG-3, and NRG-4). The NRG-1 protein, binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. The other NRGs proteins bind one or the other or both of these ErbBs. NRG-1 has multiple functions: in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors, while in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. Less is known of the functions of the other NRGs. NRG-2 and NRG-3 are expressed predominantly in the nervous system. NRG-2 is expressed by motor neurons and terminal Schwann cells, and is concentrated near synaptic sites and may be a signal that regulates synaptic differentiation. NRG-4 has been shown to direct pancreatic islet cell development towards the delta-cell lineage.

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gi 157694526 763 AAVGDLLELHCEALRGSPLILYRFFHEDVTLgNRSSP--------SGGASLNLS-LTAEHSGNYSCEADNGLGaQRSETV 833
Cdd:cd05750   11 VQEGSKLVLKCEATSENPSPRYRWFKDGKEL-NRKRPknikirnkKKNSELQINkAKLEDSGEYTCVVENILG-KDTVTG 88

                 ....
gi 157694526 834 TLYI 837
Cdd:cd05750   89 NVTV 92

Second Ig-like domain of Junctional adhesion molecule-1 (JAM1); a member of the I-set of IgSF domains; The members here are composed of the second Ig-like domain of Junctional adhesion molecule-1 (JAM1). JAM1 is an immunoglobulin superfamily (IgSF) protein with two Ig-like domains in its extracellular region; it plays a role in the formation of endothelial and epithelial tight junction and acts as a receptor for mammalian reovirus sigma-1. The IgSF is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. The two sheets are linked together by a conserved disulfide bond between B strand and F strand. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The second Ig-like domain of JAM1 is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, the A strand of the I-set is discontinuous but lacks a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors.

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gi 157694526 473 PVLTLSSAEALtfeGATVTLHCEVQRGSPQILYQFYHEDMPL---------WSSST----PSVGRVSFSfSLTEGHSGNY 539
Cdd:cd20950    1 PTVNIPSSATI---GNRAVLTCSEPDGSPPSEYTWFKDGVVMptnpkstraFSNSSysldPTTGELVFD-PLSASDTGEY 76

                         90
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gi 157694526 540 YCTADNGFG-PQRSEVVSL 557
Cdd:cd20950   77 SCEARNGYGtPMRSNAVRM 95

Third immunoglobulin domain in Cluster of Differentiation (CD) 22; member of the Constant 2 (C2)-set of IgSF domains; The members here are composed of the third immunoglobulin domain in Cluster of Differentiation (CD) 22 (also known as Siglec-2). CD22, a sialic-acid binding immunoglobulin type-lectin (Siglec) family member, is an inhibitory co-receptor of the B-cell receptor (BCR). The inhibitory function of CD22 and its restricted expression on B cells makes CD22 an attractive target against dysregulated B cells that cause autoimmune diseases and B-cell-derived cancers. CD22 plays a vital role in establishing a baseline level of B-cell inhibition, and thus is an important determinant of homeostasis in humoral immunity. Siglecs are primarily expressed on immune cells and recognize sialic acid-containing glycan ligands. Siglecs are organized as an extracellular module composed of Ig-like domains (an N-terminal variable set of Ig-like carbohydrate recognition domains, and 1 to 16 constant Ig-like domains), followed by transmembrane and short cytoplasmic domains. Human Siglecs are classified into two subgroups, one subgroup is comprised of sialoadhesin (Siglec-1), CD22 (Siglec-2), and MAG (Siglec-4, myelin-associated glycoprotein), the other subgroup is comprised of CD33-related Siglecs which include CD33 (Siglec-3) and human Siglecs 5-11. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. This group belongs to the C2-set of IgSF domains, having A, B, and E strands in one beta-sheet and A', G, F, C' in the other. Unlike other Ig domain sets, the C2-set lacks the D strand.

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gi 157694526 475 LTLSSAEALTFEGATVTLHCEVQRGSPQILYQFYHEDmplwSSSTPSVGRVSFSFS-LTEGHSGNYYCTADNGFGPQRSE 553
Cdd:cd20937    5 IKVTPSDAIVREGDSVTMTCEVSSSNPEYTTVSWLKD----GTSLKKQNTFTLNLReVTKDQSGKYCCQVSNDVGPGRSE 80

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gi 157694526 554 VVSLFV 559
Cdd:cd20937   81 EVFLQV 86