First immunoglobulin (Ig)-like domain of carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM); The members here are composed of the immunoglobulin (Ig)-like domain 1 in carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) proteins. 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 21314600  36 LTIEAVPSNAAEGKEVLLLVHNLPQDPRGYNWYKGETVDANRRIIGYVISNQQITPGPAYSNRETIYPNASLLMRNVTRN 115
Cdd:cd05774   1 LTIELVPPQVAEGENVLLLVHNLPENLLAYAWYKGKTVSPNFLIASYIISTNSSTPGPAYSGRETIYPNGSLLIQNVTQK 80

                        90       100
                ....*....|....*....|....*
gi 21314600 116 DTGSYTLQVIKLNLMSEEVTGQFSV 140
Cdd:cd05774  81 DTGFYTLQTITADLQTEQASVHLQV 105

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 21314600 243 SPSDTYYHAGVNLNLSCHAASNPPSQYSWSVNGTFQQYTQKLFIPNITTKNSGSYACHTTNSATGRNRTTVRMITV 318
Cdd:cd20948   1 SPSDTYYLSGENLNLSCHAASNPPAQYSWTINGTFQTSSQELFLPAITENNEGTYTCSAHNSLTGKNISLVLSVTV 76

First immunoglobulin (Ig)-like domain of carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM); The members here are composed of the immunoglobulin (Ig)-like domain 1 in carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) proteins. 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 21314600  36 LTIEAVPSNAAEGKEVLLLVHNLPQDPRGYNWYKGETVDANRRIIGYVISNQQITPGPAYSNRETIYPNASLLMRNVTRN 115
Cdd:cd05774   1 LTIELVPPQVAEGENVLLLVHNLPENLLAYAWYKGKTVSPNFLIASYIISTNSSTPGPAYSGRETIYPNGSLLIQNVTQK 80

                        90       100
                ....*....|....*....|....*
gi 21314600 116 DTGSYTLQVIKLNLMSEEVTGQFSV 140
Cdd:cd05774  81 DTGFYTLQTITADLQTEQASVHLQV 105

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 21314600 243 SPSDTYYHAGVNLNLSCHAASNPPSQYSWSVNGTFQQYTQKLFIPNITTKNSGSYACHTTNSATGRNRTTVRMITV 318
Cdd:cd20948   1 SPSDTYYLSGENLNLSCHAASNPPAQYSWTINGTFQTSSQELFLPAITENNEGTYTCSAHNSLTGKNISLVLSVTV 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 21314600    38 IEAVPSNAAEGKEVLLLVHNLPQDPRG---YNWYKGETVDANRR-IIGYVISNQQITPGPAYSNRETI-YPNASLLMRNV 112
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSMSEAstsVYWYRQPPGKGPTFlIAYYSNGSEEGVKKGRFSGRGDPsNGDGSLTIQNL 80

                          90       100
                  ....*....|....*....|....*....
gi 21314600   113 TRNDTGSYTLQVIKLNLMSEEVTGQFSVH 141
Cdd:pfam07686  81 TLSDSGTYTCAVIPSGEGVFGKGTRLTVL 109

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 21314600    244 PSDTYYHAGVNLNLSCHAASNPPSQYSWSVNG------------TFQQYTQKLFIPNITTKNSGSYACHTTNSATGRNRT 311
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKQGgkllaesgrfsvSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSG 80

                   .
gi 21314600    312 T 312
Cdd:smart00410  81 T 81

IL-1 receptor-like protein; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 21314600   94 AYSNRETIYPNA------SLLMRNVTRNDTGSYTLQVIKLNLmSEEVTGQFSVHPETPKPSISSNNSNPVEDKDAVAFtc 167
Cdd:PHA02826  81 ARTKIKKITHNEigdrseNLWIGNVINIDEGIYICTISSGNI-CEESTIRLTFDSGTINYQFNSGKDSKLHCYGTDGI-- 157

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|
gi 21314600  168 EPETQNTTYLWWVNGQSLPVSPRLQLSNGNRTLTLLSVTRNDVGPYECEI 217
Cdd:PHA02826 158 SSTFKDYTLTWYKNGNIVLYTDRIQLRNNNSTLVIKSATHDDSGIYTCNL 207

First immunoglobulin (Ig)-like domain of carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM); The members here are composed of the immunoglobulin (Ig)-like domain 1 in carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) proteins. 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 21314600  36 LTIEAVPSNAAEGKEVLLLVHNLPQDPRGYNWYKGETVDANRRIIGYVISNQQITPGPAYSNRETIYPNASLLMRNVTRN 115
Cdd:cd05774   1 LTIELVPPQVAEGENVLLLVHNLPENLLAYAWYKGKTVSPNFLIASYIISTNSSTPGPAYSGRETIYPNGSLLIQNVTQK 80

                        90       100
                ....*....|....*....|....*
gi 21314600 116 DTGSYTLQVIKLNLMSEEVTGQFSV 140
Cdd:cd05774  81 DTGFYTLQTITADLQTEQASVHLQV 105

Immunoglobulin (Ig)-like domain of carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) and similar proteins; The members here are composed of the immunoglobulin (Ig)-like domain in carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) and related 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. 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. This family corresponds to the D1 Ig-like domain. Also belonging to this group is the N-terminal immunoglobulin (Ig)-like domain of the signaling lymphocyte activation molecule (SLAM) family, CD84-like family. The SLAM family is a group of immune-cell specific receptors that can regulate both adaptive and innate immune responses. SLAM family proteins are organized as an extracellular domain with having 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        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 21314600  37 TIEAVpsNAAEGKEVLLLVHNLPQDPRGYNWYKGETVDANRRIIGYVISNQQITPGPAYSNRETIYPNASLLMRNVTRND 116
Cdd:cd05741   1 SSEQF--YGAEGKNVLLLVPNLQTPLKSVSWYKGKQVSRNDEIAEYENSSDEFRAGSAFSGREYIYTNGSLLIQNITLSD 78

                        90       100
                ....*....|....*....|....
gi 21314600 117 TGSYTLQVIKLNLMSEEVTGQFSV 140
Cdd:cd05741  79 TGFYTLESTNIGGKTESATFQLHV 102

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 21314600   239 APTISPSDTYYHAGVNLNLSCHAASNPPSQYSWSVNGTFQQYTQKLFIPNITTKNSGSYACHTTNSATG 307
Cdd:pfam13895   1 KPVLTPSPTVVTEGEPVTLTCSAPGNPPPSYTWYKDGSAISSSPNFFTLSVSAEDSGTYTCVARNGRGG 69

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 21314600   241 TISPSDTYYHAGVNLNLSCHAASNPPSQYSWSVNGT-----------FQQYTQKLFIPNITTKNSGSYACHTTN 303
Cdd:pfam13927   5 TVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEpissgstrsrsLSGSNSTLTISNVTRSDAGTYTCVASN 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 21314600    244 PSDTYYHAGVNLNLSCHAASNPPSQYSWSVNG------------TFQQYTQKLFIPNITTKNSGSYACHTTNSATGRNRT 311
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKQGgkllaesgrfsvSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSG 80

                   .
gi 21314600    312 T 312
Cdd:smart00410  81 T 81

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 21314600 255 LNLSCHAASNPPSQYSWSVNG-----------TFQQYTQKLFIPNITTKNSGSYACHTTNSATGRNRTTV 313
Cdd:cd00096   1 VTLTCSASGNPPPTITWYKNGkplppssrdsrRSELGNGTLTISNVTLEDSGTYTCVASNSAGGSASASV 70

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 21314600 163 VAFTCEPE-TQNTTYLWWVNGQSLPVSPRL--QLSNGNRTLTLLSVTRNDVGPYECEIQNPASANFSDPV 229
Cdd:cd00096   1 VTLTCSASgNPPPTITWYKNGKPLPPSSRDsrRSELGNGTLTISNVTLEDSGTYTCVASNSAGGSASASV 70

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 21314600 244 PSDTYYHAGV---NLNLSCHAASNPPSQYSWSVNGT---------FQQYTQKLFIPN-ITTKNSGSYACHTTNS 304
Cdd:cd05850   9 PSSTLFPEGSaeeKVTLACRARASPPATYRWKMNGTelkmepdsrYRLVAGNLVISNpVKAKDAGSYQCLASNR 82

IL-1 receptor-like protein; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 21314600   94 AYSNRETIYPNA------SLLMRNVTRNDTGSYTLQVIKLNLmSEEVTGQFSVHPETPKPSISSNNSNPVEDKDAVAFtc 167
Cdd:PHA02826  81 ARTKIKKITHNEigdrseNLWIGNVINIDEGIYICTISSGNI-CEESTIRLTFDSGTINYQFNSGKDSKLHCYGTDGI-- 157

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|
gi 21314600  168 EPETQNTTYLWWVNGQSLPVSPRLQLSNGNRTLTLLSVTRNDVGPYECEI 217
Cdd:PHA02826 158 SSTFKDYTLTWYKNGNIVLYTDRIQLRNNNSTLVIKSATHDDSGIYTCNL 207

First immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs), and similar domains; The members here are composed of the first 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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 21314600 160 KDAVAFTCE----PETQNTTylWWVNGQSLPVSPRlqlsngnrTLTLLSVTRNDVGPYECEIQNPASanfSDPVTLNV 233
Cdd:cd05752  15 GEKVTLTCQgfysPEQNSTQ--WYHNGTLISSTSS--------SYRIVAATVNDSGEYRCQTQGSSL---SDPVHLEV 79

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 21314600   146 KPSISSNNSNpVEDKDAVAFTCE-PETQNTTYLWWVNGQSLPVSPRLQLSNgnrtltllsVTRNDVGPYECEIQNPASAN 224
Cdd:pfam13895   1 KPVLTPSPTV-VTEGEPVTLTCSaPGNPPPSYTWYKDGSAISSSPNFFTLS---------VSAEDSGTYTCVARNGRGGK 70

                  ....*....
gi 21314600   225 FSDPVTLNV 233
Cdd:pfam13895  71 VSNPVELTV 79

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
                ....*....|....*....|....*....|....*....|....*..
gi 21314600 173 NTTYLWWVNGQSLPVSPRLQLSNGNRTLTLLSVTrnDVGPYECEIQN 219
Cdd:cd05728  28 RPAYRWLKNGQPLASENRIEVEAGDLRITKLSLS--DSGMYQCVAEN 72

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 21314600 244 PSDTYYHAGVNLNLSCHAASNPPSQYSWSVNGT-------FQQYTQKLFIPNITTKNSGSYACHTTN 303
Cdd:cd05728   6 ISDTEADIGSSLRWECKASGNPRPAYRWLKNGQplasenrIEVEAGDLRITKLSLSDSGMYQCVAEN 72

Immunoglobulin (Ig)-like domain of the human basement membrane heparan sulfate proteoglycan perlecan and similar proteins; The members here are composed of the immunoglobulin (Ig)-like domain of the human basement membrane heparan sulfate proteoglycan perlecan, also known as HSPG2, and similar proteins. Perlecan consists of five domains: domain I has three putative heparan sulfate attachment sites, domain II has four LDL receptor-like repeats, and one Ig-like repeat, domain III resembles the short arm of laminin chains, domain IV has multiple Ig-like repeats (21 repeats in human perlecan), and domain V resembles the globular G domain of the laminin A chain and internal repeats of EGF. Perlecan may participate in a variety of biological functions including cell binding, LDL-metabolism, basement membrane assembly and selective permeability, calcium binding, and growth- and neurite-promoting activities.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 21314600 163 VAFTCEPETQNTTYL-WWVNGQSLPVSPRLQL--SNGNRTLTLLSVTRNDVGPYECEIQNPASANFSDP 228
Cdd:cd05743   4 VEFTCVATGVPTPIInWRLNWGHVPDSARVSItsEGGYGTLTIRDVKESDQGAYTCEAINTRGMVFGIP 72

fimbrial outer membrane usher protein TcfC; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 21314600  229 VTLNVLYGPDAPTISPSDTYYHAGVNLnlscHAASNPPSQYSWSVNGT--FQQYTQKLFIPNITTKNSGSYACHTTNSAT 306
Cdd:PRK15310 570 MSVSVSYASQPPTMTGSNGYTSAGTDI----HSSRNQKTQTSWNVNHVrsWQQDLYRELSVGFSGYNDDSWSGSLGGRMS 645

                         90       100
                 ....*....|....*....|....*.
gi 21314600  307 GRNRTTVRMITVSDALVQGSSPGLSA 332
Cdd:PRK15310 646 GRMGELSATISNSHQRNAGSASSLTA 671

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 21314600 244 PSDTYYHAGV---NLNLSCHAASNPPSQYSWSVNGT---------FQQYTQKLFIPN-ITTKNSGSYACHTTNS 304
Cdd:cd04967   8 PDDTIFPEDSdekKVALNCRARANPVPSYRWLMNGTeidlesdyrYSLVDGTLVISNpSKAKDAGHYQCLATNT 81

N-terminal immunoglobulin (Ig)-like domain of T-cell surface antigen CD2, and similar domains; The members here are composed of the N-terminal immunoglobulin (Ig)-like domain (or domain 1) of T-cell surface antigen Clusters of Differentiation (CD) 2 and similar proteins. CD2 is a T-cell specific surface glycoprotein and is critically important for mediating adhesion between T cells and antigen-presenting cells or between cytolytic T cells and target cells. CD2 is located on chromosome 1 at 1p13 in humans and on chromosome 3 in mice. CD2 contains an extracellular domain with two or Ig-like domains, a single transmembrane segment, and a cytoplasmic region rich in proline and basic residues.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 21314600  44 NAAEGKEVLLLVHNLPQDPRGYNWYKgetvdaNRRIIGYVISNQQITPGPAYSNRETIYPNA-SLLMRNVTRNDTGSYTL 122
Cdd:cd05775   6 YGALGGNVTLTISSLQDDIDEIKWKK------TKDKIVEWENNIGPTYFGSFKDRVLLDKESgSLTIKNLTKEDSGTYEL 79

                ....*.
gi 21314600 123 QVIKLN 128
Cdd:cd05775  80 EITSTN 85

Immunoglobulin Variable (IgV) domain of T cell Immunoglobulin Domain and Mucin Domain 3 (Tim-3), and similar domains; The members here are composed of the immunoglobulin variable (IgV) domain of T cell immunoglobulin domain and mucin domain 3 (Tim-3; also known as Hepatitis A virus cellular receptor 2 (HAVcr-2) and Cluster of Differentiation 366 (CD366)) and similar proteins. TIM-3 is a checkpoint inhibitor in immune responses to tumors, as well as involved in chronic viral infections. Thus, Tim-3 has emerged as one of most promising immune checkpoint targets for cancer immunotherapy. Tim-3 is highly expressed on Th1 lymphocytes and CD11b(+) macrophages and is upregulated on activated T and myeloid cells. TIM-3 regulates macrophage, activation and inhibits Th1 mediated immune responses to promote immunological tolerance. There are three TIM family members in humans (TIM-1, TIM-3, and TIM-4) and eight members in mice (TIM-1 to TIM-8). The IgV domain of human TIM-3 has been shown to bind ligands such as carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1), high mobility group protein B1 (HMGB1)and galectin-9 (GAL9). The binding of GAL9 to TIM-3 can negatively regulate Th1 immune response, enhance immune tolerance and inhibit anti#tumor immunity. Dysregulation of the TIM-3/GAL9 pathway is implicated in numerous chronic autoimmune diseases, such as multiple sclerosis and systemic lupus erythematosus.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 21314600 169 PETQNTTYLWWVNGQSLPV--SPRLQL----SNGNRTLTLLSVTRNDVGPYECEIQNPASANFSD 227
Cdd:cd20982  36 PVSYCGNVLLRTDERDVTYqkSSRYQLkgdfSKGDVSLTIENVTLADSGIYCCRIQIPGIMNDEK 100