Immunoglobulin (Ig)-like domain of human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) domains 2, 4, and 6, and similar domains; The members here are composed of the second, fourth, and sixth immunoglobulin (Ig)-like domains in human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) protein subfamily. 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. This group represents the CEACAM subfamily. CEACAM1 has many important cellular functions; it is a cell adhesion molecule and a signaling molecule that regulates the growth of tumor cells, an angiogenic factor, and a receptor for bacterial and viral pathogens, including mouse hepatitis virus (MHV). In mice, four isoforms of CEACAM1 generated by alternative splicing have either two [D1, D4] or four [D1-D4] Ig-like domains on the cell surface.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 164663836 148 KPSISSSNLNPREAMETVILTCNPETPDASYLWWMNGQSLPMTHRMQLSETNRTLFLFGVTKYTAGPYECEIWNSGSASR 227
Cdd:cd05740    1 KPFISSNNSNPVEDKDAVTLTCEPETQNTSYLWWFNGQSLPVTPRLTLSNGNRTLTLLNVTREDAGAYQCEISNPVSANR 80

                 ....*....
gi 164663836 228 SDPVTLNLL 236
Cdd:cd05740   81 SDPVTLDVI 89

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 164663836 246 PSVTSYYSGENLDLSCFANSNPPAQYSWTINGKFQLSGQKLFIPQITPKHNGLYACSARNSATGEESSTSLTIRV 320
Cdd:cd20948    2 PSDTYYLSGENLNLSCHAASNPPAQYSWTINGTFQTSSQELFLPAITENNEGTYTCSAHNSLTGKNISLVLSVTV 76

Immunoglobulin (Ig)-like domain of human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) domains 2, 4, and 6, and similar domains; The members here are composed of the second, fourth, and sixth immunoglobulin (Ig)-like domains in human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) protein subfamily. 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. This group represents the CEACAM subfamily. CEACAM1 has many important cellular functions; it is a cell adhesion molecule and a signaling molecule that regulates the growth of tumor cells, an angiogenic factor, and a receptor for bacterial and viral pathogens, including mouse hepatitis virus (MHV). In mice, four isoforms of CEACAM1 generated by alternative splicing have either two [D1, D4] or four [D1-D4] Ig-like domains on the cell surface.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 164663836 148 KPSISSSNLNPREAMETVILTCNPETPDASYLWWMNGQSLPMTHRMQLSETNRTLFLFGVTKYTAGPYECEIWNSGSASR 227
Cdd:cd05740    1 KPFISSNNSNPVEDKDAVTLTCEPETQNTSYLWWFNGQSLPVTPRLTLSNGNRTLTLLNVTREDAGAYQCEISNPVSANR 80

                 ....*....
gi 164663836 228 SDPVTLNLL 236
Cdd:cd05740   81 SDPVTLDVI 89

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 164663836 246 PSVTSYYSGENLDLSCFANSNPPAQYSWTINGKFQLSGQKLFIPQITPKHNGLYACSARNSATGEESSTSLTIRV 320
Cdd:cd20948    2 PSDTYYLSGENLNLSCHAASNPPAQYSWTINGTFQTSSQELFLPAITENNEGTYTCSAHNSLTGKNISLVLSVTV 76

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 164663836   38 IEAQPPKVSEGKDVLLLVHNLPQ---NLTGYIWYKGQ-IRDLYHYITSYVVDGQIIIYGPAYSGRETV-YSNASLLIQNV 112
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSmseASTSVYWYRQPpGKGPTFLIAYYSNGSEEGVKKGRFSGRGDPsNGDGSLTIQNL 80

                          90
                  ....*....|....*...
gi 164663836  113 TREDAGSYTLHIIKRGDG 130
Cdd:pfam07686  81 TLSDSGTYTCAVIPSGEG 98

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 164663836  148 KPSISSSNLNPREAM-ETVILTCNPE-TPDASYLWWMNGQSLP--MTHRMQLSETNRTLFLFGVTKYTAGPYECEIWN 221
Cdd:pfam13927   1 KPVITVSPSSVTVREgETVTLTCEATgSPPPTITWYKNGEPISsgSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

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

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 164663836    45 VSEGKDVLLLVHnLPQNLTGYI-WYKGqirdlyhyitsyvvDGQIIIYGPAYSGRETvYSNASLLIQNVTREDAGSYT 121
Cdd:smart00410   6 VKEGESVTLSCE-ASGSPPPEVtWYKQ--------------GGKLLAESGRFSVSRS-GSTSTLTISNVTPEDSGTYT 67

Immunoglobulin (Ig)-like domain of human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) domains 2, 4, and 6, and similar domains; The members here are composed of the second, fourth, and sixth immunoglobulin (Ig)-like domains in human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) protein subfamily. 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. This group represents the CEACAM subfamily. CEACAM1 has many important cellular functions; it is a cell adhesion molecule and a signaling molecule that regulates the growth of tumor cells, an angiogenic factor, and a receptor for bacterial and viral pathogens, including mouse hepatitis virus (MHV). In mice, four isoforms of CEACAM1 generated by alternative splicing have either two [D1, D4] or four [D1-D4] Ig-like domains on the cell surface.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 164663836 148 KPSISSSNLNPREAMETVILTCNPETPDASYLWWMNGQSLPMTHRMQLSETNRTLFLFGVTKYTAGPYECEIWNSGSASR 227
Cdd:cd05740    1 KPFISSNNSNPVEDKDAVTLTCEPETQNTSYLWWFNGQSLPVTPRLTLSNGNRTLTLLNVTREDAGAYQCEISNPVSANR 80

                 ....*....
gi 164663836 228 SDPVTLNLL 236
Cdd:cd05740   81 SDPVTLDVI 89

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 164663836 246 PSVTSYYSGENLDLSCFANSNPPAQYSWTINGKFQLSGQKLFIPQITPKHNGLYACSARNSATGEESSTSLTIRV 320
Cdd:cd20948    2 PSDTYYLSGENLNLSCHAASNPPAQYSWTINGTFQTSSQELFLPAITENNEGTYTCSAHNSLTGKNISLVLSVTV 76

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 164663836  242 PRIFPSVTSYYSGENLDLSCFANSNPPAQYSWTINGKFQLSGQKLFIPQITPKHNGLYACSARNSATGeESSTSLTIRV 320
Cdd:pfam13895   2 PVLTPSPTVVTEGEPVTLTCSAPGNPPPSYTWYKDGSAISSSPNFFTLSVSAEDSGTYTCVARNGRGG-KVSNPVELTV 79

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 164663836   246 PSVTSYYSGENLDLSCFANSNPPAQYSW--------TINGKFQLSGQK----LFIPQITPKHNGLYACSARNSATGEESS 313
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPEVTWykqggkllAESGRFSVSRSGststLTISNVTPEDSGTYTCAATNSSGSASSG 80

                   ....*
gi 164663836   314 TSLTI 318
Cdd:smart00410  81 TTLTV 85

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 164663836  242 PRI--FPSVTSYYSGENLDLSCFANSNPPAQYSWTINGK-----------FQLSGQKLFIPQITPKHNGLYACSARN 305
Cdd:pfam13927   2 PVItvSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEpissgstrsrsLSGSNSTLTISNVTRSDAGTYTCVASN 78

agrin-responsive first immunoglobulin-like domains (Ig1) of the MuSK ectodomain; a member of the I-set of IgSF domains; The members here are composed of the first immunoglobulin-like domains (Ig1) of the Muscle-specific kinase (MuSK). MuSK is a receptor tyrosine kinase specifically expressed in skeletal muscle, where it plays a central role in the formation and maintenance of the neuromuscular junction (NMJ). MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. The activation of MUSK in myotubes regulates the formation of NMJs through the regulation of different processes including the specific expression of genes in subsynaptic nuclei, the reorganization of the actin cytoskeleton and the clustering of the acetylcholine receptors (AChR) in the postsynaptic membrane. 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 MuSK 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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 164663836 254 GENLDLSCFANSNPPAQYSWTINGK----------FQLSGQKLFIPQITPKHNGLYACSARNSATGEESS 313
Cdd:cd20970   17 GENATFMCRAEGSPEPEISWTRNGNliiefntryiVRENGTTLTIRNIRRSDMGIYLCIASNGVPGSVEK 86

Sixth immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the sixth immunoglobulin domain of the Drosophila melanogaster Down syndrome cell adhesion molecule (DSCAM) protein and similar proteins. Down syndrome cell adhesion molecule (DSCAM) is a cell adhesion molecule that plays critical roles in neural development, including axon guidance and branching, axon target recognition, self-avoidance and synaptic formation. DSCAM belongs to the immunoglobulin superfamily and contributes to defects in the central nervous system in Down syndrome patients. Vertebrate DSCAMs differ from Drosophila Dscam1 in that they lack the extensive alternative splicing that occurs in the insect gene. Drosophila melanogaster Dscam has 38,016 isoforms generated by the alternative splicing of four variable exon clusters, which allows every neuron in the fly to display a distinctive set of Dscam proteins on its cell surface. Drosophila Dscam1 is a cell-surface protein that plays important roles in neural development and axon tiling of neurons. It is shown that thousands of isoforms bind themselves through specific homophilic (self-binding) interactions, a process which mediates cellular self-recognition. Drosophila Dscam2 is also alternatively spliced and plays a key role in the development of two visual system neurons, monopolar cells L1 and L2. This group 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, members of the I-set have a discontinuous A strand but lack a C" strand.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 164663836 241 LPRIFP---SVTSYYSGENLDLSC-FANSNPPAQYSWTINGK---------FQLSGQK---LFIPQITPKHNGLYACSAR 304
Cdd:cd20959    1 PPRIIPfafGEGAAQVGMRAQLHCgVPGGDLPLNIRWTLDGQpisddlgitVSRLGRRssiLSIDSLEASHAGNYTCHAR 80

                         90
                 ....*....|....
gi 164663836 305 NSATGEESSTSLTI 318
Cdd:cd20959   81 NSAGSASYTAPLTV 94

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 164663836 165 VILTCNPE-TPDASYLWWMNGQSLP--MTHRMQLSETNRTLFLFGVTKYTAGPYECEIWNSGSASRSDPV 231
Cdd:cd00096    1 VTLTCSASgNPPPTITWYKNGKPLPpsSRDSRRSELGNGTLTISNVTLEDSGTYTCVASNSAGGSASASV 70

Third immunoglobulin (Ig) domain of contactin-1; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third immunoglobulin (Ig) domain of the neural cell adhesion molecule contactin-1. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. 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
                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 164663836 254 GENLDLSCFANSNPPAQYSWT-------INGKFQLSGQKLFIPQITPKHNGLYACSARN 305
Cdd:cd05851   16 GQNVTLECFALGNPVPVIRWRkilepmpATAEISMSGAVLKIFNIQPEDEGTYECEAEN 74

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

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 164663836   163 ETVILTCNPETPDASYLWWM--NGQSLPMTHRMQLSE--TNRTLFLFGVTKYTAGPYECEIWNSG 223
Cdd:smart00410  10 ESVTLSCEASGSPPPEVTWYkqGGKLLAESGRFSVSRsgSTSTLTISNVTPEDSGTYTCAATNSS 74

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 164663836  254 GENLDLSCFANSNPPAQYSWTINGK-------FQLS----GQKLFIPQITPKHNGLYACSARNSATGEESSTSLTI 318
Cdd:pfam07679  15 GESARFTCTVTGTPDPEVSWFKDGQplrssdrFKVTyeggTYTLTISNVQPDDSGKYTCVATNSAGEAEASAELTV 90

N-terminal immunoglobulin (Ig)-like domain of the signaling lymphocyte activation molecule (SLAM) family; The members here are composed of the N-terminal immunoglobulin (Ig)-like domain of the signaling lymphocyte activation molecule (SLAM) family and similar proteins. The SLAM family is a group of immune-cell specific receptors that can regulate both adaptive and innate immune responses. Members of this group include proteins such as CD84, SLAM (CD150), Ly-9 (CD229), NTB-A (ly-108, SLAM6), 19A (CRACC), and SLAMF9. The genes coding for the SLAM family are nested on chromosome 1, in humans at 1q23, and in mice at 1H2. The SLAM family is a subset of the CD2 family, which also includes CD2 and CD58 located on chromosome 1 at 1p13 in humans. In mice, CD2 is located on chromosome 3, and there is no CD58 homolog. The SLAM family proteins are organized as an extracellular domain with either two or four Ig-like domains, a single transmembrane segment, and a cytoplasmic region having Tyr-based motifs. The extracellular domain is organized as a membrane-distal Ig variable (IgV) domain that is responsible for ligand recognition and a membrane-proximal truncated Ig constant-2 (IgC2) domain.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 164663836  87 QIIIYGPAYSGRETVYSNA-SLLIQNVTREDAGSYTLHIIkrgdgTRGVTGYFT--FTLYL 144
Cdd:cd16842   46 EIIITDKSYKERLNISQNDySLQISNLTMEDAGSYRARIN-----TKNSRVTITkeFTLHI 101

Fourth Ig domain of the neural cell adhesion molecule contactin-2, and similar domains; The members here are composed of the fourth Ig domain of the neural cell adhesion molecule contactin-2. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. Contactin-2 (also called TAG-1, axonin-1) facilitates cell adhesion by homophilic binding between molecules in apposed membranes. The first four Ig domains form the intermolecular binding fragment which arranges as a compact U-shaped module by contacts between Ig domains 1 and 4, and domains 2 and 3. It has been proposed that a linear zipper-like array forms, from contactin-2 molecules alternatively provided by the two apposed membranes.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 164663836 254 GENLDLSCFANSNPPAQYSWTING-------KFQLSGQKLFIPQITPKHNGLYACSARNSATGEESSTSLTI 318
Cdd:cd05728   14 GSSLRWECKASGNPRPAYRWLKNGqplasenRIEVEAGDLRITKLSLSDSGMYQCVAENKHGTIYASAELAV 85

Fourth immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM); The members here are composed of the fourth immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 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.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 164663836 251 YYSGENLDLSCFANSNPPAQYSWTING----------KFQLSGQKLFIPQITPKHNGLYACSARN 305
Cdd:cd05867   11 YGPGETARLDCQVEGIPTPNITWSINGapiegtdpdpRRHVSSGALILTDVQPSDTAVYQCEARN 75

Fourth immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin domain of the Drosophila melanogaster Down syndrome cell adhesion molecule (DSCAM) protein and similar proteins. Down syndrome cell adhesion molecule (DSCAM) is a cell adhesion molecule that plays critical roles in neural development, including axon guidance and branching, axon target recognition, self-avoidance and synaptic formation. DSCAM belongs to the immunoglobulin superfamily and contributes to defects in the central nervous system in Down syndrome patients. Vertebrate DSCAMs differ from Drosophila Dscam1 in that they lack the extensive alternative splicing that occurs in the insect gene. Drosophila melanogaster Dscam has 38,016 isoforms generated by the alternative splicing of four variable exon clusters, which allows every neuron in the fly to display a distinctive set of Dscam proteins on its cell surface. Drosophila Dscam1 is a cell-surface protein that plays important roles in neural development and axon tiling of neurons. It is shown that thousands of isoforms bind themselves through specific homophilic (self-binding) interactions, a process which mediates cellular self-recognition. Drosophila Dscam2 is also alternatively spliced and plays a key role in the development of two visual system neurons, monopolar cells L1 and L2. This group 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, members of the I-set have a discontinuous A strand but lack a C" strand.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 164663836 254 GENLDLSCFANSNPPAQYSWTINGK-------FQLsGQK----------LFIPQITPKHNGLYACSARNSA 307
Cdd:cd20956   16 GPSVSLKCVASGNPLPQITWTLDGFpipesprFRV-GDYvtsdgdvvsyVNISSVRVEDGGEYTCTATNDV 85

First immunoglobulin (Ig) domain of contactin-2; member of the I-set of Ig superfamily domains; The members here are composed of the first immunoglobulin (Ig) domain of the neural cell adhesion molecule contactin-2-like. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. Contactin-2 (TAG-1, axonin-1) facilitates cell adhesion by homophilic binding between molecules in apposed membranes. It may play a part in the neuronal processes of neurite outgrowth, axon guidance and fasciculation, and neuronal migration. The first four Ig domains form the intermolecular binding fragment, which arranges as a compact U-shaped module by contacts between IG domains 1 and 4, and domains 2 and 3. 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-2 is also expressed in retinal amacrine cells in the developing chick retina, corresponding to the period of formation and maturation of AC processes. This group belongs to the I-set of IgSF domains.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 164663836 246 PSVTSYYSG---ENLDLSCFANSNPPAQYSWTING---------KFQLSGQKLFI--PQiTPKHNGLYACSARNS 306
Cdd:cd05850    9 PSSTLFPEGsaeEKVTLACRARASPPATYRWKMNGtelkmepdsRYRLVAGNLVIsnPV-KAKDAGSYQCLASNR 82

Fifth immunoglobulin (Ig) domain of contactin; The members here are composed of the fifth 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.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 164663836 165 VILTCNPE-TPDASYLWWMNGQSLPMTHRMQLSEtNRTLFLFGVTKYTAGPYECEIWNS-GSASRS 228
Cdd:cd04969   20 VIIECKPKaSPKPTISWSKGTELLTNSSRICILP-DGSLKIKNVTKSDEGKYTCFAVNFfGKANST 84

Third immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the Constant 2 (C2)-set of IgSF domains; The members here are composed of the third immunoglobulin domain of the Drosophila melanogaster Down syndrome cell adhesion molecule (DSCAM) protein and similar proteins. Down syndrome cell adhesion molecule (DSCAM) is a cell adhesion molecule that plays critical roles in neural development, including axon guidance and branching, axon target recognition, self-avoidance and synaptic formation. DSCAM belongs to the immunoglobulin superfamily and contributes to defects in the central nervous system in Down syndrome patients. Vertebrate DSCAMs differ from Drosophila Dscam1 in that they lack the extensive alternative splicing that occurs in the insect gene. Drosophila melanogaster Dscam has 38,016 isoforms generated by the alternative splicing of four variable exon clusters, which allows every neuron in the fly to display a distinctive set of Dscam proteins on its cell surface. Drosophila Dscam1 is a cell-surface protein that plays important roles in neural development and axon tiling of neurons. It is shown that thousands of isoforms bind themselves through specific homophilic (self-binding) interactions, a process which mediates cellular self-recognition. Drosophila Dscam2 is also alternatively spliced and plays a key role in the development of two visual system neurons, monopolar cells L1 and L2. 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, and C' in the other. Unlike other Ig domain sets, the C2-set lacks the D strand.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 164663836 244 IFPSVTSYYSGENLDLSCFANSNPPAQYSWTINGK--------FQLSGQKLFIPQITPKHNGLYACSARNSATGEESSTS 315
Cdd:cd20957    6 IDPPVQTVDFGRTAVFNCSVTGNPIHTVLWMKDGKplghssrvQILSEDVLVIPSVKREDKGMYQCFVRNDGDSAQATAE 85

                 ...
gi 164663836 316 LTI 318
Cdd:cd20957   86 LKL 88

Immunoglobulin Variable (IgV) domain in HERV-H LTR-associating 2 (HHLA2); The members here are composed of the immunoglobulin variable (IgV) region in HERV-H LTR-associating 2 (HHLA2; also known as B7-H7/B7 homolog 7). HHLA2 is a member of the B7 family of immune regulatory proteins. Mature human HHLA2 consists of an extracellular domain (ECD) with three immunoglobulin-like domains, a transmembrane segment, and a cytoplasmic domain. HHLA2 is widely expressed in human cancers including non-small cell lung carcinoma (NSCLS), triple negative breast cancer (TNBC), and melanoma, but has limited expression on normal tissues. Interestingly, unlike other members of B7 family, HHLA2 is not expressed in mice or rats. HHLA2 functions as a T cell coinhibitory molecules as it inhibits the proliferation of activated CD4(+) and CD8(+) T cells and their cytokine production. Furthermore, HHLA2 is constitutively expressed on the surface of human monocytes and is induced on B cells after stimulation, however it is not inducible on T cells.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 164663836  67 WYKGQIRDLYH--YITSYVVDGQiiiyGPAYSGRETVYS------NASLLIQNVTREDAGSYTLHI 124
Cdd:cd16091   31 WYKQDSDIKVHsyYYGKDQLESQ----DQRYRNRTSLFKdqisngNASLLLRRVQLQDEGRYKCYT 92

Immunoglobulin (Ig)-like domain of NrCAM (Ng (neuronglia) CAM-related cell adhesion molecule); member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the first immunoglobulin (Ig)-like domain of NrCAM (Ng (neuronglia) CAM-related cell adhesion molecule). NrCAM 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. NrCAM is primarily expressed in the nervous system.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 164663836 255 ENLDLSCFANSNPPAQYSWTINGK-FQLSGQklfiPQITPKHN------------------GLYACSARNSaTGEESSTS 315
Cdd:cd05874   17 ENIVIQCEAKGKPPPSFSWTRNGThFDIDKD----PKVTMKPNtgtlvinimngekaeayeGVYQCTARNE-RGAAVSNN 91

                 ....
gi 164663836 316 LTIR 319
Cdd:cd05874   92 IVIR 95

Fifth immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fifth immunoglobulin domain of the Drosophila melanogaster Down syndrome cell adhesion molecule (DSCAM) protein and similar proteins. Down syndrome cell adhesion molecule (DSCAM) is a cell adhesion molecule that plays critical roles in neural development, including axon guidance and branching, axon target recognition, self-avoidance and synaptic formation. DSCAM belongs to the immunoglobulin superfamily and contributes to defects in the central nervous system in Down syndrome patients. Vertebrate DSCAMs differ from Drosophila Dscam1 in that they lack the extensive alternative splicing that occurs in the insect gene. Drosophila melanogaster Dscam has 38,016 isoforms generated by the alternative splicing of four variable exon clusters, which allows every neuron in the fly to display a distinctive set of Dscam proteins on its cell surface. Drosophila Dscam1 is a cell-surface protein that plays important roles in neural development and axon tiling of neurons. It is shown that thousands of isoforms bind themselves through specific homophilic (self-binding) interactions, a process which mediates cellular self-recognition. Drosophila Dscam2 is also alternatively spliced and plays a key role in the development of two visual system neurons, monopolar cells L1 and L2. This group 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, members of the I-set have a discontinuous A strand but lack a C" strand.

                         10        20
                 ....*....|....*....|....*
gi 164663836  98 RETVYSNASLLIQNVTR-EDAGSYT 121
Cdd:cd20958   46 RQRVFPNGTLVIENVQRsSDEGEYT 70