Immunoglobulin variable domain (IgV) in Cluster of Differentiation (CD) 80; The members here are composed of the immunoglobulin variable region (IgV) in the Cluster of Differentiation (CD) 80). Glycoproteins B7-1 (also known as cluster of differentiation (CD) 80) and B7-2 (also known as CD86) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (also known as cluster of differentiation 152/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        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907116316  47 DEQLSKSVKDKVLLPCRYNSPHEDESEDRIYWQKHDKVVLSVIAGKLKVWPEYKNRTLYDNT-TYSLIILGLVLSDRGTY 125
Cdd:cd16086     1 IIQVTKSVKEKALLSCDYNVSVDELAQVRIYWQKDDKMVLTIISGDVKVWPEYKNRTLFDITnNLSIVILALRLSDRGTY 80

                          90       100
                  ....*....|....*....|....*
gi 1907116316 126 SCVVQKKERGTYEVKHLALVKLSIK 150
Cdd:cd16086    81 TCVVQKKERGAYKREHLASVTLSVR 105

Immunoglobulin variable domain (IgV) in Cluster of Differentiation (CD) 80; The members here are composed of the immunoglobulin variable region (IgV) in the Cluster of Differentiation (CD) 80). Glycoproteins B7-1 (also known as cluster of differentiation (CD) 80) and B7-2 (also known as CD86) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (also known as cluster of differentiation 152/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        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907116316  47 DEQLSKSVKDKVLLPCRYNSPHEDESEDRIYWQKHDKVVLSVIAGKLKVWPEYKNRTLYDNT-TYSLIILGLVLSDRGTY 125
Cdd:cd16086     1 IIQVTKSVKEKALLSCDYNVSVDELAQVRIYWQKDDKMVLTIISGDVKVWPEYKNRTLFDITnNLSIVILALRLSDRGTY 80

                          90       100
                  ....*....|....*....|....*
gi 1907116316 126 SCVVQKKERGTYEVKHLALVKLSIK 150
Cdd:cd16086    81 TCVVQKKERGAYKREHLASVTLSVR 105

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907116316 155 TPNITESGNPSAdTKRITCFASGGFPKPRFSWLENGRELPGINTTISQDPESELYTISSQLDFNTTR---NHTIKCLIKY 231
Cdd:pfam08205   4 EPPASLLEGEGP-EVVATCSSAGGKPAPRITWYLDGKPLEAAETSSEQDPESGLVTVTSELKLVPSRsdhGQSLTCQVSY 82

                  ....*.
gi 1907116316 232 GDAHVS 237
Cdd:pfam08205  83 GALRGS 88

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907116316   48 EQLSKSVKDKVLLPCRYNSPhedeSEDRIYWQKHDKVvlsviagklkvWPEYKNRTL--YDNTTYSLIILGLVLSDRGTY 125
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGS----PPPEVTWYKQGGK-----------LLAESGRFSvsRSGSTSTLTISNVTPEDSGTY 66

                   ....
gi 1907116316  126 SCVV 129
Cdd:smart00410  67 TCAA 70

Immunoglobulin variable domain (IgV) in Cluster of Differentiation (CD) 80; The members here are composed of the immunoglobulin variable region (IgV) in the Cluster of Differentiation (CD) 80). Glycoproteins B7-1 (also known as cluster of differentiation (CD) 80) and B7-2 (also known as CD86) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (also known as cluster of differentiation 152/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        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907116316  47 DEQLSKSVKDKVLLPCRYNSPHEDESEDRIYWQKHDKVVLSVIAGKLKVWPEYKNRTLYDNT-TYSLIILGLVLSDRGTY 125
Cdd:cd16086     1 IIQVTKSVKEKALLSCDYNVSVDELAQVRIYWQKDDKMVLTIISGDVKVWPEYKNRTLFDITnNLSIVILALRLSDRGTY 80

                          90       100
                  ....*....|....*....|....*
gi 1907116316 126 SCVVQKKERGTYEVKHLALVKLSIK 150
Cdd:cd16086    81 TCVVQKKERGAYKREHLASVTLSVR 105

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907116316 155 TPNITESGNPSAdTKRITCFASGGFPKPRFSWLENGRELPGINTTISQDPESELYTISSQLDFNTTR---NHTIKCLIKY 231
Cdd:pfam08205   4 EPPASLLEGEGP-EVVATCSSAGGKPAPRITWYLDGKPLEAAETSSEQDPESGLVTVTSELKLVPSRsdhGQSLTCQVSY 82

                  ....*.
gi 1907116316 232 GDAHVS 237
Cdd:pfam08205  83 GALRGS 88

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 1907116316 156 PNIT--ESGNPSADTKRITCFASGGFPKPRFSWLENGRELPGINTTISQDPESELYTISSQLDFNTTRNH---TIKCLIK 230
Cdd:cd07705     7 PQITgyESAFKEKDKAKLRCTSSGSKPAANIKWRKGDQELEGAPTSVQEDGNGKTFTVSSSVEFQVTREDdgaEITCSVG 86

                          90
                  ....*....|....
gi 1907116316 231 YGDAHVSEDFTWEK 244
Cdd:cd07705    87 HESLHDSDRSTSQR 100

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 1907116316  41 QVSSDVDEQLSKSVKdkvlLPCRYNSPHEDESeDRIYW--QKHDKVVLSVIAGKLKVWPE------YKNRTLYDNTTYSL 112
Cdd:pfam07686   1 QTPREVTVALGGSVT----LPCTYSSSMSEAS-TSVYWyrQPPGKGPTFLIAYYSNGSEEgvkkgrFSGRGDPSNGDGSL 75

                          90       100
                  ....*....|....*....|....*.
gi 1907116316 113 IILGLVLSDRGTYSCVVQKKERGTYE 138
Cdd:pfam07686  76 TIQNLTLSDSGTYTCAVIPSGEGVFG 101

Second immunoglobulin (Ig)-like domain of the nectin-like molecules Necl-1 - Necl-4; member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of the nectin-like molecules Necl-1 (also known as cell adhesion molecule 3 or CADM3), Necl-2 (also known as CADM1), Necl-3 (also known as CADM2) and Necl-4 (also known as CADM4). 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. Necl-3 has been shown to accumulate in tissues of the central and peripheral nervous system, where it is expressed in ependymal cells and myelinated axons. It is observed at the interface between the axon shaft and the myelin sheath. Necl-4 is expressed on Schwann cells, and plays a key part in initiating peripheral nervous system (PNS) myelination. Necl-4 participates in cell-cell adhesion and is proposed to play a role in tumor suppression.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1907116316 167 DTKRITCFASGGFPKPRFSWLENGRELPGInTTISQDPESELYTISSQLDFNTTRN 222
Cdd:cd05761    20 DEITLTCTTSGSKPAADIRWFKNDKELKGV-KEVQESGAGKTFTVTSTLRFRVDRD 74

Second immunoglobulin (Ig)-like domain of nectin-like molecule-3 (Necl-3); member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of nectin-like molecule-3 (Necl-3; also known as cell adhesion molecule 2 (CADM2)). 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. Necl-3 has been shown to accumulate in tissues of the central and peripheral nervous system where it is expressed in ependymal cells and myelinated axons. It is observed at the interface between the axon shaft and the myelin sheath. Ig domains are likely to participate in ligand binding and recognition.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1907116316 156 PNITESGNP--SADTKRITCFASGGFPKPRFSWLENGRELPGINTTISQDPESELYTISSQLDFNTTRN 222
Cdd:cd05884     8 PQISGFTSPvmEGDHIQLTCKTSGSKPAADIRWFKNDKEVKDVKYLKAEDANRKTFTVSSSLDFHVDRD 76

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 1907116316  50 LSKSVKDKVLLPCRYNSPHedeSEDRIYW--QKHDKV---VLSVIAGKLKVWPEYKNR---TLYDNTTYSLIILGLVLSD 121
Cdd:cd00099     8 LSVQEGESVTLSCEVSSSF---SSTYIYWyrQKPGQGpefLIYLSSSKGKTKGGVPGRfsgSRDGTSSFSLTISNLQPED 84

                  ....*...
gi 1907116316 122 RGTYSCVV 129
Cdd:cd00099    85 SGTYYCAV 92

Signal-regulatory protein (SIRP) immunoglobulin-like domain 2; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in Signal-Regulatory Protein (SIRP), domain 2 (C1 repeat 1). The SIRPs belong to the "paired receptors" class of membrane proteins that comprise several genes coding for proteins with similar extracellular regions, but very different transmembrane/cytoplasmic regions with different (activating or inhibitory) signaling potentials. They are commonly on NK cells, but are also on many myeloid cells. Their extracellular region contains three Immunoglobulin superfamily domains, a single V-set and two C1-set IgSF domains. Their cytoplasmic tails contain either ITIMs or transmembrane regions that have positively charged residues that allow an association with adaptor proteins, such as DAP12/KARAP, containing ITAMs. There are 3 distinct SIRP members: alpha, beta, and gamma. SIRP alpha (also known as CD172a or SRC homology 2 domain-containing protein tyrosine phosphatase substrate 1/Shps-1) is a membrane receptor that interacts with a ligand CD47 expressed on many cells and gives an inhibitory signal through immunoreceptor tyrosine-based inhibition motifs in the cytoplasmic region that interact with phosphatases SHP-1 and SHP-2. SIRP beta has a short cytoplasmic region and associates with a transmembrane adapter protein DAP12 containing immunoreceptor tyrosine-based activation motifs to give an activating signal. SIRP gamma contains a very short cytoplasmic region lacking obvious signaling motifs, but also binds CD47, but with much less affinity.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1907116316 171 ITCFASGGFPKP-RFSWLENGRELPGINTTISQDPESELYTISS 213
Cdd:cd05772    22 FTCKSHGFSPRDiTLKWFKNGNELSALQTTVFPEGDSVSYSVSS 65