Second immunoglobulin (Ig)-like domain of nectin-like molcule-1 (Necl-1); member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of nectin-like molcule-1 (Necl-1; also known as cell adhesion molecule3 (CADM3)). These nectin-like molecules have similar domain structures to those of nectins. At least five nectin-like molecules have been identified (Necl-1 through Necl-5). These have an extracellular region containing three Ig-like domains, one transmembrane region, and one cytoplasmic region. The N-terminal Ig-like domain of the extracellular region belongs to the V-type subfamily of Ig domains is essential to cell-cell adhesion and plays a part in the interaction with the envelope glycoprotein D of various viruses. Necl-1 and Necl-2 have Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity. Necl-1 is specifically expressed in neural tissue and is important to the formation of synapses, axon bundles, and myelinated axons. Necl-2 is expressed in a wide variety of tissues and is a putative tumour suppressor gene which is downregulated in aggressive neuroblastoma. Ig domains are likely to participate in ligand binding and recognition.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 210 LGIPQKPIITGYKSSLREKDTATLNCQSSGSKPAARLTWRKGDQELHGEPTRIQEDPNGKTFTVSSSVTFQVTREDDGAS 289
Cdd:cd07705     1 LGIPQKPQITGYESAFKEKDKAKLRCTSSGSKPAANIKWRKGDQELEGAPTSVQEDGNGKTFTVSSSVEFQVTREDDGAE 80

                          90       100
                  ....*....|....*....|...
gi 1370454064 290 IVCSVNHESLKGADRSTSQRIEV 312
Cdd:cd07705    81 ITCSVGHESLHDSDRSTSQRIEV 103

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064  328 REGQKLLLHCEGRGNPVPQQYlWEKEGSVPPL--------KMTQESALIFPFLNKSDSGTYGCTATSNMGSYKAYYTLNV 399
Cdd:smart00410   7 KEGESVTLSCEASGSPPPEVT-WYKQGGKLLAesgrfsvsRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTLTV 85

Second immunoglobulin (Ig)-like domain of nectin-like molcule-1 (Necl-1); member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of nectin-like molcule-1 (Necl-1; also known as cell adhesion molecule3 (CADM3)). These nectin-like molecules have similar domain structures to those of nectins. At least five nectin-like molecules have been identified (Necl-1 through Necl-5). These have an extracellular region containing three Ig-like domains, one transmembrane region, and one cytoplasmic region. The N-terminal Ig-like domain of the extracellular region belongs to the V-type subfamily of Ig domains is essential to cell-cell adhesion and plays a part in the interaction with the envelope glycoprotein D of various viruses. Necl-1 and Necl-2 have Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity. Necl-1 is specifically expressed in neural tissue and is important to the formation of synapses, axon bundles, and myelinated axons. Necl-2 is expressed in a wide variety of tissues and is a putative tumour suppressor gene which is downregulated in aggressive neuroblastoma. Ig domains are likely to participate in ligand binding and recognition.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 210 LGIPQKPIITGYKSSLREKDTATLNCQSSGSKPAARLTWRKGDQELHGEPTRIQEDPNGKTFTVSSSVTFQVTREDDGAS 289
Cdd:cd07705     1 LGIPQKPQITGYESAFKEKDKAKLRCTSSGSKPAANIKWRKGDQELEGAPTSVQEDGNGKTFTVSSSVEFQVTREDDGAE 80

                          90       100
                  ....*....|....*....|...
gi 1370454064 290 IVCSVNHESLKGADRSTSQRIEV 312
Cdd:cd07705    81 ITCSVGHESLHDSDRSTSQRIEV 103

CD80-like C2-set immunoglobulin domain; These domains belong to the immunoglobulin superfamily.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 216 PIITGYKSSLREKDT-ATLNCQSSGSKPAARLTWRKGDQELHGEPTRIQEDPNGKTFTVSSSVTFQVTREDDGASIVCSV 294
Cdd:pfam08205   1 PTIEPPASLLEGEGPeVVATCSSAGGKPAPRITWYLDGKPLEAAETSSEQDPESGLVTVTSELKLVPSRSDHGQSLTCQV 80

                  ....*..
gi 1370454064 295 NHESLKG 301
Cdd:pfam08205  81 SYGALRG 87

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064  328 REGQKLLLHCEGRGNPVPQQYlWEKEGSVPPL--------KMTQESALIFPFLNKSDSGTYGCTATSNMGSYKAYYTLNV 399
Cdd:smart00410   7 KEGESVTLSCEASGSPPPEVT-WYKQGGKLLAesgrfsvsRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTLTV 85

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 1370454064 122 TVVAGGTVVLKCQVK---DHEDSSLQWS------NPAQQTLYFGEKRA--LRDNRIQLVTSTP-HELSISISNVALADEG 189
Cdd:pfam07686   7 TVALGGSVTLPCTYSssmSEASTSVYWYrqppgkGPTFLIAYYSNGSEegVKKGRFSGRGDPSnGDGSLTIQNLTLSDSG 86

                          90
                  ....*....|
gi 1370454064 190 EYTCSIFTMP 199
Cdd:pfam07686  87 TYTCAVIPSG 96

Immunoglobulin (Ig) constant domain of the complement receptor of the immunoglobulin superfamily (CRIg); The members here are composed of the Immunoglobulin (Ig) constant domain of the complement receptor of the immunoglobulin superfamily (CRIg). The N-terminal domain of CRIg (also referred to as Z39Ig and V-set and Ig domain-containing 4 (VSIG4)) belongs to the IgV family of immunoglobulin-like domains while the C-terminal domain of CRIg belongs to the IgC family of immunoglobulin-like domains. CRIg plays a role in the complement system, an inhibitor of the alternative pathway convertases, and a negative regulator of T cell activation. 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 such as T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins such as 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.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1370454064 329 EGQKLLLHCEGRGNPvPQQYLWEKE--GSVPPLKMTQESALIFPFLNKSDSGTYGCTATSNMGS 390
Cdd:cd16082    12 QGMRISLQCQAWGSP-PISYVWYKEqtNNQEPIKVAALSTLLFKPAVVADSGSYFCTAKGRVGS 74

Second immunoglobulin (Ig)-like domain of nectin-like molcule-1 (Necl-1); member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of nectin-like molcule-1 (Necl-1; also known as cell adhesion molecule3 (CADM3)). These nectin-like molecules have similar domain structures to those of nectins. At least five nectin-like molecules have been identified (Necl-1 through Necl-5). These have an extracellular region containing three Ig-like domains, one transmembrane region, and one cytoplasmic region. The N-terminal Ig-like domain of the extracellular region belongs to the V-type subfamily of Ig domains is essential to cell-cell adhesion and plays a part in the interaction with the envelope glycoprotein D of various viruses. Necl-1 and Necl-2 have Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity. Necl-1 is specifically expressed in neural tissue and is important to the formation of synapses, axon bundles, and myelinated axons. Necl-2 is expressed in a wide variety of tissues and is a putative tumour suppressor gene which is downregulated in aggressive neuroblastoma. Ig domains are likely to participate in ligand binding and recognition.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 210 LGIPQKPIITGYKSSLREKDTATLNCQSSGSKPAARLTWRKGDQELHGEPTRIQEDPNGKTFTVSSSVTFQVTREDDGAS 289
Cdd:cd07705     1 LGIPQKPQITGYESAFKEKDKAKLRCTSSGSKPAANIKWRKGDQELEGAPTSVQEDGNGKTFTVSSSVEFQVTREDDGAE 80

                          90       100
                  ....*....|....*....|...
gi 1370454064 290 IVCSVNHESLKGADRSTSQRIEV 312
Cdd:cd07705    81 ITCSVGHESLHDSDRSTSQRIEV 103

First (N-terminal) immunoglobulin (Ig)-like domain of the nectin-like molecules; member of the V-set of Ig superfamily (IgSF) domains; The members here are composed of the N-terminal immunoglobulin (Ig)-like domain of the nectin-like molecules Necl-1 (also known as cell adhesion molecule 3 (CADM3)), Necl-2 (CADM1), Necl-3 (CADM2), and similar proteins. At least five nectin-like molecules have been identified (Necl-1 to Necl-5). They all have an extracellular region containing three Ig-like domains, a transmembrane region, and a cytoplasmic region. The N-terminal Ig-like domain of the extracellular region belongs to the V-type subfamily of Ig domains, is essential to cell-cell adhesion, and plays a part in the interaction with the envelope glycoprotein D of various viruses. Necl-1, Necl-2, and Necl-3 have Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity. Necl-1 is specifically expressed in neural tissue, and is important to the formation of synapses, axon bundles, and myelinated axons. Necl-2 is expressed in a wide variety of tissues and is a putative tumour suppressor gene which is downregulated in aggressive neuroblastoma. Necl-3 accumulates in central and peripheral nervous system tissue and has been shown to selectively interact with oligodendrocytes. This group also contains Class-I MHC-restricted T-cell-associated molecule (CRTAM), whose expression pattern is consistent with its expression in Class-I MHC-restricted T-cells.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 116 PWTSDETVVAGGTVVLKCQVKDHEDSSLQWSNPAQQTLYFGEKRALRDNRIQLVTSTPHELSISISNVALADEGEYTCSI 195
Cdd:cd05717     1 PHTQDVTVVEGETLTLKCQVSLRDDSSLQWLNPNGQTIYFNDKRALRDSRYQLLNHSASELSISVSNVTLSDEGVYTCLH 80

                          90
                  ....*....|....
gi 1370454064 196 FTMPVRTAKSLVTV 209
Cdd:cd05717    81 YTDPVSTKKVTVTV 94

First (N-terminal) immunoglobulin (Ig)-like domain of nectin-like molecule-3; member of the V-set of Ig superfamily (IgSF) domains; The members here are composed of the N-terminal immunoglobulin (Ig)-like domain of nectin-like molecule-3, Necl-3 (also known as cell adhesion molecule 2 (CADM2), SynCAM2, IGSF4D). Nectin-like molecules have similar domain structures to those of nectins. At least five nectin-like molecules have been identified (Necl-1 - Necl-5). They all have an extracellular region containing three Ig-like domains, a transmembrane region, and a cytoplasmic region. The N-terminal Ig-like domain of the extracellular region, belongs to the V-type subfamily of Ig domains, is essential to cell-cell adhesion, and plays a part in the interaction with the envelope glycoprotein D of various viruses. Necl-3 accumulates in central and peripheral nervous system tissue, and has been shown to selectively interact with oligodendrocytes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 116 PWTSDETVVAGGTVVLKCQVKDHEDSSLQWSNPAQQTLYFGEKRALRDNRIQLVTSTPHELSISISNVALADEGEYTCSI 195
Cdd:cd07701     2 PLTQNVTVVEGGTANLTCRVDQNDNTSLQWSNPAQQTLYFDDKKALRDNRIELVRASWHELSISISDVSLSDEGQYTCSL 81

                          90
                  ....*....|....*
gi 1370454064 196 FTMPVRTAKSLVTVL 210
Cdd:cd07701    82 FTMPVKTSKAYLTVL 96

First (N-terminal) immunoglobulin (Ig)-like domain of nectin-like molecule 2; member of the V-set of Ig superfamily (IgSF) domains; The members here are composed of the N-terminal immunoglobulin (Ig)-like domain of nectin-like molecule-2, Necl-2 (also known as cell adhesion molecule 1 (CADM1), SynCAM1, IGSF4A, Tslc1, sgIGSF, and RA175). Nectin-like molecules have similar domain structures to those of nectins. At least five nectin-like molecules have been identified (Necl-1 - Necl-5). They all have an extracellular region containing three Ig-like domains, a transmembrane region, and a cytoplasmic region. The N-terminal Ig-like domain of the extracellular region, belongs to the V-type subfamily of Ig domains, is essential to cell-cell adhesion, and plays a part in the interaction with the envelope glycoprotein D of various viruses. Necl-2 has Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity. Necl-2 is expressed in a wide variety of tissues and is a putative tumour suppressor gene, which is downregulated in aggressive neuroblastoma.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 118 TSDETVVAGGTVVLKCQVKDHEDSSLQWSNPAQQTLYFGEKRALRDNRIQLVTSTPHELSISISNVALADEGEYTCSIFT 197
Cdd:cd05881     3 TEDVTVVEGEVATISCRVKNSDDSVIQLLNPNRQTIYFRDFRPLKDSRFQLVNFSSSELRVSLTNVSISDEGRYFCQLYT 82

                          90
                  ....*....|..
gi 1370454064 198 MPVRTAKSLVTV 209
Cdd:cd05881    83 DPPQEAYTTITV 94

CD80-like C2-set immunoglobulin domain; These domains belong to the immunoglobulin superfamily.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 216 PIITGYKSSLREKDT-ATLNCQSSGSKPAARLTWRKGDQELHGEPTRIQEDPNGKTFTVSSSVTFQVTREDDGASIVCSV 294
Cdd:pfam08205   1 PTIEPPASLLEGEGPeVVATCSSAGGKPAPRITWYLDGKPLEAAETSSEQDPESGLVTVTSELKLVPSRSDHGQSLTCQV 80

                  ....*..
gi 1370454064 295 NHESLKG 301
Cdd:pfam08205  81 SYGALRG 87

Second immunoglobulin (Ig) domain of Nectin-2 and Nectin-like protein 5, and similar domains; member of the C1-set of the Ig superfamily (IgSF) domains; The members here are composed of the second immunoglobulin (Ig) domain of nectin-2 (also known as poliovirus receptor related protein 2 or Cluster of Differentiation 112 (CD112)), nectin-like protein 5 (CD155), and similar proteins. Nectins and Nectin-like molecules are a family of Ca(2+)-independent immunoglobulin-like transmembrane glycoproteins belonging to the class of adhesion receptors, consisting of nine members (nectins 1 through 4 and nectin-like proteins 1 through 5). Nectins are synaptic cell adhesion molecules (CAMs) which facilitate adhesion and signaling at various intracellular junctions. Nectins form homophilic cis-dimers, followed by homophilic and heterophilic trans-dimers involved in cell-cell adhesion. Nectin-2 and nectin-3 localize at Sertoli-spermatid junctions where they form heterophilic trans-interactions between the cells that are essential for the formation and maintenance of the junctions and for spermatid development. CD155 is the fifth member in the nectin-like molecule family, and functions as the receptor of poliovirus; therefore, CD155 is also referred to as Necl-5, or PVR. In contrast to all other family members, CD155 lacks self-adhesion capacity, yet it shares with nectins the feature to interact with other nectins. For instance, CD155 heterophilically trans-interacts with nectin-3, thereby contributing significantly to the establishment of adherens junctions between epithelial cells. This group belongs to the Constant 1 (C1)-set of IgSF domains, which has one beta-sheet that is formed by strands A-B-E-D and the other strands by G-F-C-C'.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1370454064 235 CQSSGSKPAARLTWRkgdQELHGEPTRIQE-DPNGKTFTVSSSVTFQVTREDDGASIVCSVNHESL 299
Cdd:cd07703    22 CVSANGRPPARISWS---STLNGNANTTQVpGPDSGTVTVTSEYSLVPTPEANGKEVTCKVEHETL 84

Second immunoglobulin (Ig) domain of poliovirus receptor (PVR, also known as CD155 and Necl-5), and similar domains; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the second immunoglobulin (Ig) domain of poliovirus receptor (PVR, also known as CD155 and nectin-like protein 5 (Necl-5)) and similar proteins. 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), these result from alternate splicing of the CD155 mRNA, and have identical extracellular domains. CD155-beta and CD155-gamma are secreted, while 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" and has a footprint similar to that of the intercellular adhesion molecule-1 receptor on human rhinoviruses. This group also includes the second Ig-like domain of nectin-1, also known as poliovirus receptor related protein(PVRL)1 or CD111.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 213 PQKPIITGYKSSLREKDTATLNCQSSGSKPAARLTWrkgDQELHGEPTRIQEDPNGKTFTVSSSVTFQVTREDDGASIVC 292
Cdd:cd05719     1 PTNSLEGGPALLIGGEPTLVATCISANGKPPASVTW---ETDLKGEASTTQVRGSNGTVTVTSRYRLVPSREADGQPLTC 77

                  ....*..
gi 1370454064 293 SVNHESL 299
Cdd:cd05719    78 VVEHPSL 84

Immunoglobulin constant (IgC)-like domain of antigen receptor Cluster of Differentiation (CD) 80; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin constant (IgC)-like domain of the antigen receptor Cluster of Differentiation (CD) 80. CD80 (also known as glycoprotein B7-1) and CD86 (also known as glycoprotein B7-2) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (CD152) on T cells. signaling through CD28 augments the T-cell response, whereas CTLA-4 signaling attenuates it. CD80 contains two Ig-like domains, an amino-terminal immunoglobulin variable (IgV)-like domain characteristic of adhesion molecules, and a membrane proximal immunoglobulin constant (IgC)-like domain similar to the constant domains of antigen receptors. Members of the Ig family are components of immunoglobulin, T-cell receptors, CD1 cell surface glycoproteins, secretory glycoproteins A/C, and major histocompatibility complex (MHC) class I/II molecules. In immunoglobulins, each chain is composed of one variable domain (IgV) and one or more IgC domains. These names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. The IgV domain is responsible for antigen binding, and the IgC domain is involved in oligomerization and molecular interactions.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1370454064 229 DTATLNCQSSGSKPAARLTWRKGDQELHGEPTRIQEDPNGKTFTVSSSVTFQVTREDdgaSIVCSVNH 296
Cdd:cd16083    15 NIKRIICSTSGGFPEPRLSWLENGEELNAINTTVSQDPETELYTVSSELDFNVTYNH---SIVCLIKY 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 1370454064  328 REGQKLLLHCEGRGNPVPQQYlWEKEGSVPPL--------KMTQESALIFPFLNKSDSGTYGCTATSNMGSYKAYYTLNV 399
Cdd:smart00410   7 KEGESVTLSCEASGSPPPEVT-WYKQGGKLLAesgrfsvsRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTLTV 85

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1370454064 316 PTAMIRPDPPHPREGQKLLLHCEGRGNPVPqQYLWEKEGSV-------PPLKMTQESALIFPFLNKSDSGTYGCTAT 385
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGSPPP-TITWYKNGEPissgstrSRSLSGSNSTLTISNVTRSDAGTYTCVAS 77

Immunoglobulin domain; Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-protein and protein-ligand interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 225 LREKDTATLNCQSSGSKPAARLTWRKGDQELHgEPTRIQEDPNGKTftvSSSVTFQVTREDDGASIVCSVNHESLKGADR 304
Cdd:pfam00047   8 VLEGDSATLTCSASTGSPGPDVTWSKEGGTLI-ESLKVKHDNGRTT---QSSLLISNVTKEDAGTYTCVVNNPGGSATLS 83

                  ...
gi 1370454064 305 STS 307
Cdd:pfam00047  84 TSL 86

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 1370454064 122 TVVAGGTVVLKCQVK---DHEDSSLQWS------NPAQQTLYFGEKRA--LRDNRIQLVTSTP-HELSISISNVALADEG 189
Cdd:pfam07686   7 TVALGGSVTLPCTYSssmSEASTSVYWYrqppgkGPTFLIAYYSNGSEegVKKGRFSGRGDPSnGDGSLTIQNLTLSDSG 86

                          90
                  ....*....|
gi 1370454064 190 EYTCSIFTMP 199
Cdd:pfam07686  87 TYTCAVIPSG 96

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1370454064 215 KPIITGYKSS--LREKDTATLNCQSSGSkPAARLTWRKGDQELHGEPTRIQE-DPNGKTFTVSSsvtfqVTREDDG 287
Cdd:pfam13927   1 KPVITVSPSSvtVREGETVTLTCEATGS-PPPTITWYKNGEPISSGSTRSRSlSGSNSTLTISN-----VTRSDAG 70

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1370454064 319 MIRPDPPHPREGQKLLLHCEGRGNPVPqQYLWEKEGSVpplkMTQESALIFPFLNKSDSGTYGCTAT 385
Cdd:pfam13895   3 VLTPSPTVVTEGEPVTLTCSAPGNPPP-SYTWYKDGSA----ISSSPNFFTLSVSAEDSGTYTCVAR 64

Third immunoglobulin (Ig)-like domain in Robo (roundabout) receptors; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third immunoglobulin (Ig)-like domain in Robo (roundabout) receptors. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, Robo2, Robo3), and three mammalian Slit homologs (Slit-1,Slit-2, Slit-3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, Robo2, and Robo3 are expressed by commissural neurons in the vertebrate spinal cord and Slit-1, Slit-2, and Slit-3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of Slit responsiveness, antagonizes Slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1370454064 330 GQKLLLHCEGRGNPVPQqYLWEKEGSVPPLKMTQ---ESALIFPFLNKSDSGTYGCTATSNMGSYKAYYTLNV 399
Cdd:cd05725    12 DDSAEFQCEVGGDPVPT-VRWRKEDGELPKGRYEildDHSLKIRKVTAGDMGSYTCVAENMVGKIEASATLTV 83

Immunoglobulin domain; Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-protein and protein-ligand interactions.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1370454064 328 REGQKLLLHCEGRGNPVPQQYLWEKEGSVPPLKM---------TQESALIFPfLNKSDSGTYGCTATSNMGSYKAYYTL 397
Cdd:pfam00047   9 LEGDSATLTCSASTGSPGPDVTWSKEGGTLIESLkvkhdngrtTQSSLLISN-VTKEDAGTYTCVVNNPGGSATLSTSL 86

First immunoglobulin (Ig) domain of contactin-5; 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-5. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains, anchored to the membrane by glycosylphosphatidylinositol. The different contactins show different expression patterns in the central nervous system. In rats, a lack of contactin-5 (NB-2) results in an impairment of the neuronal activity in the auditory system. Contactin-5 is expressed specifically in the postnatal nervous system, peaking at about 3 weeks postnatal. Contactin-5 is highly expressed in the adult human brain in the occipital lobe and in the amygdala; lower levels of expression have been detected in the corpus callosum, caudate nucleus, and spinal cord. This group belongs to the I-set of IgSF domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 316 PTAMIRPDP---PHPREGQKLLLHCEGRGNPVPqQYLWEKEGSVPPLKMTQESALI---FPFLNKS---DSGTYGCTATS 386
Cdd:cd05848     2 PVFVQEPDDaifPTDSDEKKVILNCEARGNPVP-TYRWLRNGTEIDTESDYRYSLIdgnLIISNPSevkDSGRYQCLATN 80

                  ....
gi 1370454064 387 NMGS 390
Cdd:cd05848    81 SIGS 84

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        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 122 TVVAGGTVVLKCQVKDHEDSSLQWsnpaqqtlyfgEK--RALRDNRIQLVTSTPhelSISISNVALA-DEGEYTCSIFTM 198
Cdd:cd20958    11 TAVAGQTLRLHCPVAGYPISSITW-----------EKdgRRLPLNHRQRVFPNG---TLVIENVQRSsDEGEYTCTARNQ 76

                          90
                  ....*....|.
gi 1370454064 199 PVRTAKSLVTV 209
Cdd:cd20958    77 QGQSASRSVFV 87

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 324 PPHP---REGQKLLLHCEGRGNPVPQqYLWEKEGSVPP----LKMTQE---SALIFPFLNKSDSGTYGCTATSNMGSYKA 393
Cdd:pfam07679   6 KPKDvevQEGESARFTCTVTGTPDPE-VSWFKDGQPLRssdrFKVTYEggtYTLTISNVQPDDSGKYTCVATNSAGEAEA 84

                  ....*.
gi 1370454064 394 YYTLNV 399
Cdd:pfam07679  85 SAELTV 90

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 1370454064 328 REGQKLLLHCEGRGNPVPQqYLWEKEGSV--PPLK------MTQESALIFPFLNKSDSGTYGCTATSNMGSYKAYYTLNV 399
Cdd:cd05763    12 RAGSTARLECAATGHPTPQ-IAWQKDGGTdfPAARerrmhvMPEDDVFFIVDVKIEDTGVYSCTAQNSAGSISANATLTV 90

Second immunoglobulin (Ig) domain of nectin-1, and similar domains; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the second immunoglobulin (Ig) domain of nectin-1 (also known as poliovirus receptor related protein 1, or cluster of differentiation (CD) 111). Nectin-1 belongs to the nectin family comprised of four transmembrane glycoproteins (nectin-1 through -4). Nectins are synaptic cell adhesion molecules (CAMs) which facilitate adhesion and signaling at various intracellular junctions. Nectins form homophilic cis-dimers, followed by homophilic and heterophilic trans-dimers involved in cell-cell adhesion. Nectins also heterophilically trans-interact with other CAMs such as nectin-like molecules (Necls); nectin-1 for example, has been shown to trans-interact with Necl-1. Nectins also interact with various other proteins, including the actin filament (F-actin)-binding protein, afadin. Mutation in the human nectin-1 gene is associated with cleft lip/palate ectodermal dysplasia syndrome (CLPED1). Nectin-1 is a major receptor for herpes simplex virus through interaction with the viral envelope glycoprotein D.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1370454064 216 PIITGYKSSLREKDTATlnCQSSGSKPAARLTWrkgDQELHGEPTrIQE--DPNGkTFTVSSSVTFQVTREDDGASIVCS 293
Cdd:cd05890    10 AVLRAKKGQDDKVLVAT--CTSANGKPPSVVSW---DTRLKGEAE-FQEirNPNG-TVTVISRYRLVPSREAHQQSLACI 82

                  ....
gi 1370454064 294 VNHE 297
Cdd:cd05890    83 VNYH 86

Fifth Ig-like domain of Roundabout (Robo) homolog 1/2, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fifth Ig-like domain of Roundabout (Robo) homolog 1/2 and similar domains. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, -2, and -3), and three mammalian Slit homologs (Slit-1,-2, -3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, -2, and -3 are expressed by commissural neurons in the vertebrate spinal cord and Slits 1, -2, -3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of slit responsiveness, antagonizes slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be is the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. The fifth Ig-like domain of Robo 1 and 2 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. 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1370454064 328 REGQKLLLHCEGRGNPVPQqYLWEKEGSV-----PPLKMTQESALIFPFLNKSDSGTYGCTATSNMGSYKAYYTLNV 399
Cdd:cd20952    12 AVGGTVVLNCQATGEPVPT-ISWLKDGVPllgkdERITTLENGSLQIKGAEKSDTGEYTCVALNLSGEATWSAVLDV 87

Third immunoglobulin (Ig) domain of contactin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1370454064 330 GQKLLLHCEGRGNPVPqQYLWEK-EGSVPPLKM--TQESALIFPFLNKSDSGTYGCTATSNMG 389
Cdd:cd04968    16 GQTVTLECFALGNPVP-QIKWRKvDGSPSSQWEitTSEPVLEIPNVQFEDEGTYECEAENSRG 77

Second immunoglobulin (Ig) domain of nectin-3 and nectin-4 (poliovirus receptor related protein 4), and similar domains; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the second immunoglobulin (Ig) domain of nectin-3 (also known as poliovirus receptor related protein 3 or cluster of differentiation (CD) 113) and nectin-4 (poliovirus receptor related protein 4). Nectin-3 and nectin-4 belong to the nectin family comprised of four transmembrane glycoproteins (nectin-1 through -4). Nectins are synaptic cell adhesion molecules (CAMs) which facilitate adhesion and signaling at various intracellular junctions. Nectins form homophilic cis-dimers, followed by homophilic and heterophilic trans-dimers involved in cell-cell adhesion. Nectin-2 and nectin-3 localize at Sertoli-spermatid junctions where they form heterophilic trans-interactions between the cells that are essential for the formation and maintenance of the junctions and for spermatid development. Nectin-3 has also been shown to form a heterophilic trans-interaction with nectin-1 in ciliary epithelia, establishing the apex-apex adhesion between the pigment and non-pigment cell layers. Nectin-4 has recently been identified in several types of breast carcinoma and can be used as a histological and serological marker for breast cancer.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1370454064 235 CQSSGSKPAARLTWrkgDQELHG-EPTRIQEDPNgkTFTVSSSVTFQVTREDDGASIVCSVNHESLKGADRST 306
Cdd:cd07704    24 CTAETGKPAASVTW---ETDLGGmESSRTFEHNR--TATVTSEYHLVPTRFANGRPLTCVVSHPALQQDIRIT 91

Fourth immunoglobulin (Ig)-like domain in Robo (roundabout) receptors; member of the I-set of Ig superfamily (IgSF) domains; Members here are composed the fourth immunoglobulin (Ig)-like domain in Robo (roundabout) receptors. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, Robo2, Robo3), and three mammalian Slit homologs (Slit-1, Slit-2, Slit-3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, Robo2, and Robo3 are expressed by commissural neurons in the vertebrate spinal cord and Slit-1, Slit-2, and Slit-3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of Slit responsiveness, antagonizes Slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. 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 1370454064 319 MIRPDPPHPREGQKLLLHCEGRGNPVPQQYlWEKEGSV-------PP-----LKMTQESALIFPFLNKSDSGTYGCTATS 386
Cdd:cd05726     3 VVKPRDQVVALGRTVTFQCETKGNPQPAIF-WQKEGSQnllfpyqPPqpssrFSVSPTGDLTITNVQRSDVGYYICQALN 81

                          90
                  ....*....|....*
gi 1370454064 387 NMGSYKAYYTLNVND 401
Cdd:cd05726    82 VAGSILAKAQLEVTD 96

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 1370454064 325 PHPREGQKLLLHCEGRGNPVPqQYLWEKEGSVPPLKMTQESALI---FPFLNKS---DSGTYGCTATSNMGS 390
Cdd:cd04967    14 PEDSDEKKVALNCRARANPVP-SYRWLMNGTEIDLESDYRYSLVdgtLVISNPSkakDAGHYQCLATNTVGS 84

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.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1370454064 330 GQKLLLHCEGRGNPVPQqYLWEKEGSV----PPLKMTQESALIFPFLNKSDSGTYGCTATSNMGSYKAYYTLNV 399
Cdd:cd04969    17 GGDVIIECKPKASPKPT-ISWSKGTELltnsSRICILPDGSLKIKNVTKSDEGKYTCFAVNFFGKANSTGSLSV 89

Immunoglobulin I-set domain of the Leucine-rich repeat and immunoglobin-like domain-containing protein 1 (Lingo-1); The members here are composed of the immunoglobulin I-set (IgI) domain of the Leucine-rich repeat and immunoglobin-like domain-containing protein 1 (Lingo-1). Human Lingo-1 is a central nervous system-specific transmembrane glycoprotein also known as LERN-1, which functions as a negative regulator of neuronal survival, axonal regeneration, and oligodendrocyte differentiation and myelination. Lingo-1 is a key component of the Nogo receptor signaling complex (RTN4R/NGFR) in RhoA activation responsible for some inhibition of axonal regeneration by myelin-associated factors. The ligand-binding ectodomain of human Lingo-1 contains a bimodular, kinked structure composed of leucine-rich repeat (LRR) and immunoglobulin (Ig)-like modules. Diseases associated with Lingo-1 include mental retardation, autosomal recessive 64 and essential tremor. 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 Lingo-1 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 1370454064 329 EGQKLLLHCEGRGNPvPQQYLWEKEGSVPPLKMTQESALIFP-------FLNKSDSGTYGCTATSNMGSYK 392
Cdd:cd20969    16 EGHTVQFVCRADGDP-PPAILWLSPRKHLVSAKSNGRLTVFPdgtlevrYAQVQDNGTYLCIAANAGGNDS 85