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 118197279 168 SSSLSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPSQpsnplVLEL-QVHLGDEGEFTCRAQNSLGSQHVSLNLSLQ 245
Cdd:cd20948    2 PSDTYYLSGENLNLSCHAASNPPAQYSWTINGTFQTSSQ-----ELFLpAITENNEGTYTCSAHNSLTGKNISLVLSVT 75

Fifth immunoglobulin (Ig)-like domain of the carcinoembryonic antigen (CEA) related cell adhesion molecule 5 (CEACAM5) and similar domains; member of the C2-set IgSF domains; The members here are composed of the fifth immunoglobulin (Ig)-like domain of the carcinoembryonic antigen (CEA) related cell adhesion molecule 5 (CEACAM5) and similar domains. The CEA family is a group of anchored or secreted glycoproteins, expressed by epithelial cells, leukocytes, endothelial cells and placenta. The CEA family is divided into the CEACAM and pregnancy-specific glycoprotein (PSG) subfamilies. Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), also known as CD66e (Cluster of Differentiation 66e), is a cell surface glycoprotein that plays a role in cell adhesion, intracellular signaling and tumor progression. Diseases associated with CEACAM5 include lung cancer and rectum cancer. 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.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 118197279 168 SSSLSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPSQpsnplVLEL-QVHLGDEGEFTCRAQNSLGSQHVSLNLSLQ 245
Cdd:cd20948    2 PSDTYYLSGENLNLSCHAASNPPAQYSWTINGTFQTSSQ-----ELFLpAITENNEGTYTCSAHNSLTGKNISLVLSVT 75

Immunoglobulin V-set domain; This domain is found in antibodies as well as neural protein P0 and CTL4 amongst others.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279   29 TMQSSVTVQEGMCVHVRCSFSYPVDSQTDSdpVhgYWFR--AGNDISWKAPVATNNpawAVQEETRDRFHLLGDPQTKNC 106
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSMSEASTS--V--YWYRqpPGKGPTFLIAYYSNG---SEEGVKKGRFSGRGDPSNGDG 73

                          90
                  ....*....|....*....
gi 118197279  107 TLSIRDARMSDAGRYFFRM 125
Cdd:pfam07686  74 SLTIQNLTLSDSGTYTCAV 92

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279    31 QSSVTVQEGMCVHVRCSFSypvdsqtDSDPVHGYWFRagNDISWKAPvatnnpawavqeetRDRFHLlgDPQTKNCTLSI 110
Cdd:smart00410   1 PPSVTVKEGESVTLSCEAS-------GSPPPEVTWYK--QGGKLLAE--------------SGRFSV--SRSGSTSTLTI 55

                           90
                   ....*....|..
gi 118197279   111 RDARMSDAGRYF 122
Cdd:smart00410  56 SNVTPEDSGTYT 67

Fifth immunoglobulin (Ig)-like domain of the carcinoembryonic antigen (CEA) related cell adhesion molecule 5 (CEACAM5) and similar domains; member of the C2-set IgSF domains; The members here are composed of the fifth immunoglobulin (Ig)-like domain of the carcinoembryonic antigen (CEA) related cell adhesion molecule 5 (CEACAM5) and similar domains. The CEA family is a group of anchored or secreted glycoproteins, expressed by epithelial cells, leukocytes, endothelial cells and placenta. The CEA family is divided into the CEACAM and pregnancy-specific glycoprotein (PSG) subfamilies. Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), also known as CD66e (Cluster of Differentiation 66e), is a cell surface glycoprotein that plays a role in cell adhesion, intracellular signaling and tumor progression. Diseases associated with CEACAM5 include lung cancer and rectum cancer. 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.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 118197279 168 SSSLSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPSQpsnplVLEL-QVHLGDEGEFTCRAQNSLGSQHVSLNLSLQ 245
Cdd:cd20948    2 PSDTYYLSGENLNLSCHAASNPPAQYSWTINGTFQTSSQ-----ELFLpAITENNEGTYTCSAHNSLTGKNISLVLSVT 75

Immunoglobulin V-set domain; This domain is found in antibodies as well as neural protein P0 and CTL4 amongst others.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279   29 TMQSSVTVQEGMCVHVRCSFSYPVDSQTDSdpVhgYWFR--AGNDISWKAPVATNNpawAVQEETRDRFHLLGDPQTKNC 106
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSMSEASTS--V--YWYRqpPGKGPTFLIAYYSNG---SEEGVKKGRFSGRGDPSNGDG 73

                          90
                  ....*....|....*....
gi 118197279  107 TLSIRDARMSDAGRYFFRM 125
Cdd:pfam07686  74 SLTIQNLTLSDSGTYTCAV 92

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279  168 SSSLSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPSQ------PSNPLVLELQ-VHLGDEGEFTCRAQNSLGSQHVSL 240
Cdd:pfam07679   7 PKDVEVQEGESARFTCTVTGTPDPEVSWFKDGQPLRSSDrfkvtyEGGTYTLTISnVQPDDSGKYTCVATNSAGEAEASA 86

                  ..
gi 118197279  241 NL 242
Cdd:pfam07679  87 EL 88

First immunoglobulin domain of Cluster of Differentiation (CD) 22; member of the V-set of IgSF domains; The members here are composed of the first 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 V-set of IgSF domains.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279  38 EGMCVHVRCSFSYPvDSQTDSDPV-HGYWFRAGNDiSWKAPVATNNPAWAVQEETRDRFHLLGDpQTKNCTLSIRDARMS 116
Cdd:cd20929   13 EGACVWIPCTYRAL-DGDLESFILfHNPEYNKATS-KFDGTRLYESTKDGKVPSEQKRVQFLGD-KNKNCTLSIHPVHLN 89

                         90
                 ....*....|....*.
gi 118197279 117 DAGRYFFRMEKGNIKW 132
Cdd:cd20929   90 DSGQLGLRMESKTEKW 105

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 118197279  167 NSSSLSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPSQpsNPLVleLQVHLGDEGEFTCRAQNSLGSqHVSLNLSLQ 245
Cdd:pfam13895   5 TPSPTVVTEGEPVTLTCSAPGNPPPSYTWYKDGSAISSSP--NFFT--LSVSAEDSGTYTCVARNGRGG-KVSNPVELT 78

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 118197279 179 LRLVCAVDSNPPARLSWTWRSLTLYPSQPSNPLVLE-------LQVHLGDEGEFTCRAQNSLGSQ 236
Cdd:cd00096    1 VTLTCSASGNPPPTITWYKNGKPLPPSSRDSRRSELgngtltiSNVTLEDSGTYTCVASNSAGGS 65

First immunoglobulin variable (IgV) domain of poliovirus receptor (PVR, also known as CD155 and necl-5), and similar domains; The members here are composed of the first immunoglobulin (Ig) domain of poliovirus receptor (PVR, also known as CD155 and nectin-like protein 5 (necl-5)). Poliovirus (PV) binds to its cellular receptor (PVR/CD155) to initiate infection. CD155 is a membrane-anchored, single-span glycoprotein; its extracellular region has three Ig-like domains. There are four different isotypes of CD155 (referred to as alpha, beta, gamma, and delta), that result from alternate splicing of the CD155 mRNA, and have identical extracellular domains. CD155-beta and CD155-gamma are secreted; CD155-alpha and CD155-delta are membrane-bound and function as PV receptors. The virus recognition site is contained in the amino-terminal domain, D1. Having the virus attachment site on the receptor distal from the plasma membrane may be important for successful initiation of infection of cells by the virus. CD155 binds in the poliovirus "canyon" with a footprint similar to that of the intercellular adhesion molecule-1 receptor on human rhinoviruses. This group also includes the first Ig-like domain of nectin-1 (also known as poliovirus receptor related protein(PVRL)1; CD111), nectin-3 (also known as PVRL 3), nectin-4 (also known as PVRL4; LNIR receptor)and DNAX accessory molecule 1 (DNAM-1; CD226).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279  33 SVTVQEGMCVHVRCSFSYPVD---SQTDsdpvhgyWFRAGNDISwkAPVATNNPAW--AVQEETRDRFHLLGDPQT-KNC 106
Cdd:cd05718    8 EVTGFLGGSVTLPCSLTSPGTtkiTQVT-------WMKIGAGSS--QNVAVFHPQYgpSVPNPYAERVEFLAARLGlRNA 78

                         90
                 ....*....|....*
gi 118197279 107 TLSIRDARMSDAGRY 121
Cdd:cd05718   79 TLRIRNLRVEDEGNY 93

Immunoglobulin (Ig)-like domain of myotilin, palladin, and myopalladin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in myotilin, palladin, and myopalladin. Myotilin, palladin, and myopalladin function as scaffolds that regulate actin organization. Myotilin and myopalladin are most abundant in skeletal and cardiac muscle; palladin is ubiquitously expressed in the organs of developing vertebrates and plays a key role in cellular morphogenesis. The three family members each interact with specific molecular partners with all three binding to alpha-actinin; In addition, palladin also binds to vasodilator-stimulated phosphoprotein (VASP) and ezrin, myotilin binds to filamin and actin, and myopalladin also binds to nebulin and cardiac ankyrin repeat protein (CARP). This group belongs to the I-set of IgSF 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, members of the I-set have a discontinuous A strand, but lack a C" strand.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279 170 SLSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPSQPSNPLVLELQVHL--------GDEGEFTCRAQNSLGSQHVSLN 241
Cdd:cd05744    9 DLEVQEGRLCRFDCKVSGLPTPDLFWQLNGKPVRPDSAHKMLVRENGRHSliiepvtkRDAGIYTCIARNRAGENSFNAE 88

                 .
gi 118197279 242 L 242
Cdd:cd05744   89 L 89

Immunoglobulin (Ig)-like ectodomain of the LRIG1 (Leucine-rich Repeats And Immunoglobulin-like Domains Protein 1) and similar proteins; member of the I-set of IgSF domains; The members here are composed of subgroup 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. 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. The ectodomain of LRIG1 has two distinct regions: the proposed 15 LRRs and three Ig-like domains closer to the membrane. LRIG1 has been reported to interact with many receptor tyrosine kinases, GDNF/c-Ret, E-cadherin, JAK/STAT, c-Met, and the EGFR family signaling systems. Immunoglobulin 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. The structure of the LRIG1 extracellular Ig domain lacks a C" strand and thus is better described as a member of the I-set of IgSF domains.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279 171 LSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPS--------QPSNPLVLELQVHLGDEGEFTCRAQNSLGSqhVSLNL 242
Cdd:cd05763    9 ITIRAGSTARLECAATGHPTPQIAWQKDGGTDFPAarerrmhvMPEDDVFFIVDVKIEDTGVYSCTAQNSAGS--ISANA 86

                 ..
gi 118197279 243 SL 244
Cdd:cd05763   87 TL 88

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM), and similar domains; The members here are composed of the third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region and an intracellular domain. L1 is primarily expressed in the nervous system and is involved in its development and function. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, and spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains the chicken neuron-glia cell adhesion molecule, Ng-CAM and human neurofascin.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 118197279 168 SSSLSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPSQPS-----NPLVLElQVHLGDEGEFTCRAQNSLGSQH 237
Cdd:cd05731    2 ESSTMVLRGGVLLLECIAEGLPTPDIRWIKLGGELPKGRTKfenfnKTLKIE-NVSEADSGEYQCTASNTMGSAR 75

Second Ig-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk and similar proteins. Titin is a key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. 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. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the titin Z1z2 lacks this strand and thus it belongs to the I-set of the IgSF. 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, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 118197279 170 SLSVLEGQSLRLVCAVDSNPPARLSWTWRSLTLYPSqpsnplvLELQVHLG--------------DEGEFTCRAQNSLGS 235
Cdd:cd20972   10 SQEVAEGSKVRLECRVTGNPTPVVRWFCEGKELQNS-------PDIQIHQEgdlhsliiaeafeeDTGRYSCLATNSVGS 82

                 ....
gi 118197279 236 QHVS 239
Cdd:cd20972   83 DTTS 86