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 966988655   30 YTSRVLEAVNGTDARLKCTFSSFvPVGDALTVTWNFRPLDGGPEQFVFYYHIDpfQPMsGRFKDRVSWDGNPERYDASIF 109
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSS-MSEASTSVYWYRQPPGKGPTFLIAYYSNG--SEE-GVKKGRFSGRGDPSNGDGSLT 76

                          90       100       110
                  ....*....|....*....|....*....|....
gi 966988655  110 LWKLQFDDNGTYTCQVkNPPDVDGVIGEIRLSVV 143
Cdd:pfam07686  77 IQNLTLSDSGTYTCAV-IPSGEGVFGKGTRLTVL 109

Immunoglobulin (Ig)-like domain of protein zero (P0) and similar proteins; The members here are composed of the immunoglobulin (Ig) domain of protein zero (P0), a myelin membrane adhesion molecule. P0 accounts for over 50% of the total protein in peripheral nervous system (PNS) myelin. P0 is a single-pass transmembrane glycoprotein with a highly basic intracellular domain and an extracellular Ig domain. The extracellular domain of P0 (P0-ED) is similar to the Ig variable domain, carrying one acceptor sequence for N-linked glycosylation. P0 plays a role in membrane adhesion in the spiral wraps of the myelin sheath. The intracellular domain is thought to mediate membrane apposition of the cytoplasmic faces and may, through electrostatic interactions, interact directly with lipid headgroups. It is thought that homophilic interactions of the P0 extracellular domain mediate membrane juxtaposition in the extracellular space of PNS myelin. This group also contains the Ig domain of sodium channel subunit beta-2 (SCN2B), and of epithelial V-like antigen 1 (EVA). EVA, also known as myelin protein zero-like 2, is an adhesion molecule, which may play a role in structural organization of the thymus and early lymphocyte development. SCN2B subunits play a role in determining sodium channel density and function in neurons,and in control of electrical excitability in the brain.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 966988655  27 VEIYTSRVLEAVNGTDARLKCTFSSFVPVGDALTVTWNFRPLDGGPEQFVFYYH-IDPFQPMSGRFKDRVSWDGNPERYD 105
Cdd:cd05715    1 MEVYTPRELNVLNGSDVRLTCTFTSCYTVGDAFSVTWTYQPEGGNTTESMFHYSkGKPYILKVGRFKDRVSWAGNPSKKD 80

                         90       100       110
                 ....*....|....*....|....*....|....*..
gi 966988655 106 ASIFLWKLQFDDNGTYTCQVKNPPDVDGVIGEIRLSV 142
Cdd:cd05715   81 ASIVISNLQFSDNGTYTCDVKNPPDIVGGHGEIRLYV 117

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 966988655   30 YTSRVLEAVNGTDARLKCTFSSFvPVGDALTVTWNFRPLDGGPEQFVFYYHIDpfQPMsGRFKDRVSWDGNPERYDASIF 109
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSS-MSEASTSVYWYRQPPGKGPTFLIAYYSNG--SEE-GVKKGRFSGRGDPSNGDGSLT 76

                          90       100       110
                  ....*....|....*....|....*....|....
gi 966988655  110 LWKLQFDDNGTYTCQVkNPPDVDGVIGEIRLSVV 143
Cdd:pfam07686  77 IQNLTLSDSGTYTCAV-IPSGEGVFGKGTRLTVL 109

Immunoglobulin Variable (V) domain of the Coxsackievirus and Adenovirus Receptor (CAR), and similar proteins; The members here are composed of the Variable (V) domain of the Coxsackievirus and Adenovirus Receptor (CAR), and similar proteins. CAR, which is encoded by human CXADR gene, is a cell adhesion molecule of the Immunoglobulin (Ig) superfamily. The CAR acts as a type I membrane receptor for group B1-B6 coxsackie viruses and subgroup C adenoviruses. For instance, adenovirus interacts with the coxsackievirus and adenovirus receptor to enter epithelial airway cells. The CAR is also shown to be involved in physiological processes such as neuronal and heart development, epithelial tight junction integrity, and tumor suppression. The CAR is a component of the epithelial apical junction complex that may function as a homophilic cell adhesion molecule and is essential for tight junction integrity. The CAR is also involved in transepithelial migration of leukocytes through adhesive interactions with JAML a transmembrane protein of the plasma membrane of leukocytes. The interaction between both receptors also mediates the activation of gamma-delta T-cells, a subpopulation of T-cells residing in epithelia and involved in tissue homeostasis and repair. The CAR is composed of one V-set and one C2-set Ig module, a single transmembrane helix, and an intracellular domain. This group belongs to the V-set of IgSF domains, having A, B, E and D strands in one beta-sheet and A', G, F, C, C' and C" in the other

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 966988655  35 LEAVNGTDARLKCTFSSFVPVGDALTVTWNFRPLDGGPEQFVFYYHIDPFQPMSGRFKDRVSWDGNPERYDASIFLWKLQ 114
Cdd:cd20960   10 IKKVAGENVTLPCHHQLGLEDQGTLDIEWLLLPSDKVEKVVITYSGDRVYNHYYPALKGRVAFTSNDLSGDASLNISNLK 89

                         90
                 ....*....|....*..
gi 966988655 115 FDDNGTYTCQVKNPPDV 131
Cdd:cd20960   90 LSDTGTYQCKVKKAPGY 106

First immunoglobulin (Ig) variable (V) domain of rat MRC OX-2 antigen, and similar domains; The members here are composed of the first immunoglobulin (Ig) domain of rat MRC OX-2 antigen (also known as CD200) and similar proteins. MRC OX-2 is a membrane glycoprotein expressed in a variety of lymphoid and non-lymphoid cells in rats. It has a similar broad distribution pattern in humans. MRC OX-2 may regulate myeloid cell activity. The protein has an extracellular portion containing two Ig-like domains, a transmembrane portion, and a cytoplasmic portion.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 966988655  33 RVLEAVNGTDARLKCTFSSfvpVGDALTVTWNfRPLDGGPEQFVFYY--HIDPFQPmsgRFKDRVSWDgNPERYDASIFL 110
Cdd:cd05846    6 GDTRAVLGGNATLSCNLTL---PEEVLQVTWQ-KIKASSPENIVTYSkkYGVKIQP---SYVRRISFT-SSGLNSTSITI 77

                         90       100
                 ....*....|....*....|.
gi 966988655 111 WKLQFDDNGTYTCQVKNPPDV 131
Cdd:cd05846   78 WNVTLEDEGCYKCLFNTFPDG 98

First immunoglobulin variable (IgV) domain of nectin-1, and similar domains; The members here are composed of the first immunoglobulin (Ig) domain of nectin-1 (also known as poliovirus receptor related protein 1 (PVRL1) or cluster of differentiation (CD) 111). Nectin-1 belongs to the nectin family comprised of four transmembrane glycoproteins (nectins-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. In addition nectins 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 966988655  40 GTDARLKCTFSSFVPVGDALTVTWnfRPLDGGPEQFVFYYHIDPFQPMSGRFKDRVSWDgNPERYDASIFLWKLQFDDNG 119
Cdd:cd05886   14 GTDVVLHCSFANPLPSVKITQVTW--QKSTNGSKQNVAIYNPSMGVSVLPPYRERVTFL-NPSFTDGTIRLSRLELEDEG 90

                         90
                 ....*....|
gi 966988655 120 TYTCQVKNPP 129
Cdd:cd05886   91 VYICEFATFP 100

First Ig-like domain of Junctional adhesion molecule-1 (JAM1)and similar domains; a member of the V-set of IgSF domains; The members here are composed of the first Ig-like domain of Junctional Adhesion Molecule-1 (JAM1)and similar domains. JAM1 is an immunoglobulin superfamily (IgSF) protein with two Ig-like domains in its extracellular region; it plays a role in the formation of endothelial and epithelial tight junction and acts as a receptor for mammalian reovirus sigma-1. The IgSF is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. The two sheets are linked together by a conserved disulfide bond between B strand and F strand. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The first Ig-like domain of JAM1 is a member of the V-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C'-C" in the other.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 966988655  33 RVLEAVNGTDARLKCTFSSFVpvgDALTVTWNFrplDGGPEQFVFYYHidpfQPMSGRFKDRVSWDGnperydASIFLWK 112
Cdd:cd20946    7 QVVTVVENQEVILSCKTPKKT---SSPRVEWKK---LQRDVTFVVFQN----NKIQGDYKGRAEILG------TNITIKN 70

                         90       100       110
                 ....*....|....*....|....*....|..
gi 966988655 113 LQFDDNGTYTCQVKNPPDVDGvIGE--IRLSV 142
Cdd:cd20946   71 VTRSDSGKYRCEVSARSDGQN-LGEvtVTLEV 101

Immunoglobulin variable domain (IgV); The members here are composed of the immunoglobulin variable domain (IgV). The IgV family contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology, and are components of immunoglobulin (Ig) and T cell receptors. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. Within the variable domain, there are regions of even more variability called the hypervariable or complementarity-determining regions (CDRs) which are responsible for antigen binding. A predominant feature of most Ig domains is the disulfide bridge connecting 2 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" strands in the other.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 966988655  31 TSRVLEAVNGTDARLKCTFSSFVPVGdalTVTWnFRPLDGGPEQFVFYYhIDPFQPMSGRFKDRVSWDGNPERydaSIFL 110
Cdd:cd00099    4 SPRSLSVQEGESVTLSCEVSSSFSST---YIYW-YRQKPGQGPEFLIYL-SSSKGKTKGGVPGRFSGSRDGTS---SFSL 75

                         90
                 ....*....|....*..
gi 966988655 111 W--KLQFDDNGTYTCQV 125
Cdd:cd00099   76 TisNLQPEDSGTYYCAV 92

Immunoglobulin (Ig)-like domain of human cartilage link protein (LP), and similar domains; The members here are composed of the immunoglobulin (Ig)-like domain similar to that found in human cartilage link protein (LP; also called hyaluronan and proteoglycan link protein). In cartilage, chondroitin-keratan sulfate proteoglycan (CSPG), aggrecan, forms cartilage link protein stabilized aggregates with hyaluronan (HA). These aggregates contribute to the tissue's load bearing properties. Aggregates having other CSPGs substituting for aggrecan may contribute to the structural integrity of many different tissues. Members of the vertebrate HPLN (hyaluronan/HA and proteoglycan binding link) protein family are physically linked adjacent to CSPG genes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 966988655  61 VTWNFRPLDGGPEQFVFY---YHIDPFqpmsGRFKDRVSWDGNPERyDASIFLWKLQFDDNGTYTCQVKNPPDVDGVIGE 137
Cdd:cd05877   35 VKWTKLEVDYAKEEDVLVaigTRHKSY----GSYQGRVFLRRADDL-DASLVITDLRLEDYGRYRCEVIDGLEDESVVVA 109

                 ...
gi 966988655 138 IRL 140
Cdd:cd05877  110 LRL 112

First immunoglobulin variable (IgV) domain of nectin-3 (also known as poliovirus receptor related protein 3), and similar domains; The members here are composed of the first immunoglobulin (Ig) domain of nectin-3 (also known as poliovirus receptor related protein 3 (PVRL3) or cluster of differentiation (CD) 113). Nectin-3 belongs to the nectin family comprised of four transmembrane glycoproteins (nectins-1 through -4). Nectins are synaptic cell adhesion molecules (CAMs) which participate in adhesion and signaling at various intracellular junctions. Nectins form homophilic cis-dimers, followed by homophilic and heterophilic trans-dimers involved in cell-cell adhesion. For example, during spermatid development, the nectin-3,-2 trans-interaction is required for the formation of Sertoli cell-spermatid junctions in testis, and during morphogenesis of the ciliary body, the nectin-3,-1 trans-interaction is important for apex-apex adhesion between the pigment and non-pigment layers of the ciliary epithelia. Nectins also heterophilically trans-interact with other CAMs such as nectin-like molecules (Necls); nectin-3 for example, trans-interacts with Necl-5, regulating cell movement and proliferation. Other proteins with which nectin-3 interacts include the actin filament-binding protein, afadin, integrin alpha-beta3, Par-3, and PDGF receptor; its interaction with PDGF receptor regulates the latter's signaling for anti-apoptosis.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 966988655  37 AVNGTDARLKCtfssFVPVGDALT-VTWnfRPLDGGPEQFVFYYHIDPFQPMSGRFKDRVSWDgNPERYDASIFLWKLQF 115
Cdd:cd05887   11 AVWGKNVSLKC----LIEVNETITqISW--EKIHGKSSQTVAVHHPQYGISIQGEYQGRVSFK-NYSLNDATITLHNVGF 83

                         90
                 ....*....|....
gi 966988655 116 DDNGTYTCQVKNPP 129
Cdd:cd05887   84 SDSGKYICKAVTFP 97

Immunoglobulin (Ig)-like domain of the chondroitin sulfate proteoglycan core protein (CSPG), neurocan; The members here are composed of the immunoglobulin (Ig)-like domain of the chondroitin sulfate proteoglycan core protein (CSPG), neurocan. In CSPGs, the Ig-like domain is followed by hyaluronan (HA)-binding tandem repeats, and a C-terminal region with epidermal growth factor-like, lectin-like, and complement regulatory protein-like domains. Separating these N- and C-terminal regions is a nonhomologous glycosaminoglycan attachment region. In cartilage, the CSPG aggrecan (not included in this group) forms cartilage link protein stabilized aggregates with HA. These aggregates contribute to the tissue's load bearing properties. Unlike aggrecan which is widely distributed in connective tissue and extracellular matrices, neurocan is localized almost exclusively in nervous tissue. Aggregates having other CSPGs substituting for aggrecan may contribute to the structural integrity of many different tissues. Members of the vertebrate HPLN (hyaluronan/HA and proteoglycan binding link) protein family are physically linked adjacent to CSPG genes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 966988655  45 LKCTFS---SFVPVGDALTVTWNFRPLDGGPEQFVFYYHIDPFQPMSGRFKDRVSWDGNPE-RYDASIFLWKLQFDDNGT 120
Cdd:cd05902   17 LPCVFTlppSASSPPEGPRIKWTKLSTSGGQQQRPVLVARDNVVRVAKAFQGRVSLPGYPKnRYNASLVLSRLRYSDSGT 96

                 ....*
gi 966988655 121 YTCQV 125
Cdd:cd05902   97 YRCEV 101