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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 145 KPSAPVVLGPAARTTPEHTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPTGQSVAYSIRSTARVVLDPWDVRSQV 224
Cdd:cd05772     1 KPSQPLVSGPSGRATPGQTVSFTCKSHGFSPRDITLKWFKNGNELSALQTTVFPEGDSVSYSVSSTVQVVLTKDDVHSQL 80

                          90       100
                  ....*....|....*....|...
gi 2462580740 225 ICEVAHVTLQgDPLRGTANLSEA 247
Cdd:cd05772    81 TCEVAHVTLQ-APLRGTANLSDI 102

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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 145 KPSAPVVLGPAARTTPEHTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPTGQSVAYSIRSTARVVLDPWDVRSQV 224
Cdd:cd05772     1 KPSQPLVSGPSGRATPGQTVSFTCKSHGFSPRDITLKWFKNGNELSALQTTVFPEGDSVSYSVSSTVQVVLTKDDVHSQL 80

                          90       100
                  ....*....|....*....|...
gi 2462580740 225 ICEVAHVTLQgDPLRGTANLSEA 247
Cdd:cd05772    81 TCEVAHVTLQ-APLRGTANLSDI 102

Immunoglobulin C1-set domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2462580740 162 HTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPTGQSVA-YSIRSTARVVLDPWDVRSQVICEVAHVTL 233
Cdd:pfam07654  13 KPNTLTCLVTGFYPPDITVTWLKNGQEVTEGVKTTPPSPNSDWtYQLSSYLTVTPSDWESGDEYTCRVEHEGL 85

Immunoglobulin V-Type;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740   48 TATLHCTV-TSLLPVGPVLWFRgVGPGREL---IYNQKEGHF-------PRVTTVSDLTKRnnmDFSIRISSITPADVGT 116
Cdd:smart00406   1 SVTLSCKFsGSTFSSYYVSWVR-QPPGKGLewlGYIGSNGSSyyqesykGRFTISKDTSKN---DVSLTISNLRVEDTGT 76

                   ...
gi 2462580740  117 YYC 119
Cdd:smart00406  77 YYC 79

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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 145 KPSAPVVLGPAARTTPEHTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPTGQSVAYSIRSTARVVLDPWDVRSQV 224
Cdd:cd05772     1 KPSQPLVSGPSGRATPGQTVSFTCKSHGFSPRDITLKWFKNGNELSALQTTVFPEGDSVSYSVSSTVQVVLTKDDVHSQL 80

                          90       100
                  ....*....|....*....|...
gi 2462580740 225 ICEVAHVTLQgDPLRGTANLSEA 247
Cdd:cd05772    81 TCEVAHVTLQ-APLRGTANLSDI 102

Immunoglobulin Constant-1 (C1)-set domain; The members here are composed of C1-set domains, classical Ig-like domains resembling the antibody constant domain. Members of the IgC1 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, while the IgC domain is involved in oligomerization and molecular interactions. 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 strands by G, F, C, and C'.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 149 PVVLGPAARTTPEHTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPT-GQSVAYSIRSTARVVLDPWDVRSQVICE 227
Cdd:cd00098     2 VTLLPPSPEEKGGGKVTLVCLVSGFYPKDITVTWLKNGVPLTSGVSTSSPVePNDGTYSVTSSLTVPPSDWDEGATYTCV 81

                  ....*..
gi 2462580740 228 VAHVTLQ 234
Cdd:cd00098    82 VTHESLK 88

Immunoglobulin C1-set domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2462580740 162 HTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPTGQSVA-YSIRSTARVVLDPWDVRSQVICEVAHVTL 233
Cdd:pfam07654  13 KPNTLTCLVTGFYPPDITVTWLKNGQEVTEGVKTTPPSPNSDWtYQLSSYLTVTPSDWESGDEYTCRVEHEGL 85

Immunoglobulin C-Type;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 2462580740  163 TVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPTGQS-VAYSIRSTARVVLDPWDVRSQVICEVAHVTLQG 235
Cdd:smart00407   1 KATLVCLVSGFYPPDITVTWLRNGQEVTEGVSTTDPLKNSdGTYFLSSYLTVPASTWESGDVYTCQVTHEGLKE 74

CH3 domain (third constant Ig domain of the heavy chain) in immunoglobulin heavy alpha, gamma, and delta chains, and CH4 domain (fourth constant Ig domain of the heavy chain) in immunoglobulin heavy alpha, epsilon, and mu chains; member of the C1-set of I; The members here are composed of the third and fourth immunoglobulin constant domain (IgC) of alpha, delta, gamma and alpha, epsilon, and mu heavy chains, respectively. This domain is found on the Fc fragment. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda; each is composed of a constant domain and a variable domain. There are five types of heavy chains: alpha, delta, epsilon, gamma, and mu, all consisting of a variable domain (VH) with three (alpha, delta and gamma) or four (epsilon and mu) constant domains (CH1 to CH4). Ig molecules are modular proteins, in which the variable and constant domains have clear, conserved sequence patterns.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 161 EHTVSFTCESHGFSPRDITLKWFKNGNELSD---FQTNVDPTGQSvAYSIRSTARVVLDPWDVRSQVICEVAHvtlQGDP 237
Cdd:cd05768    16 NETVTLTCLVKGFYPEDIFVSWLQNGEPLPSadyKTTAPVPESDG-SFFVYSKLNVSTADWNSGDVFSCVVGH---EALP 91

                  ..
gi 2462580740 238 LR 239
Cdd:cd05768    92 LQ 93

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 2462580740  36 QPEKLLLVTVGKTATLHCTVTSLLPVGPVLWFRGvgpGRELIYNQKEGHFPRVTTVSDLTkrnnmdfsirISSITPADVG 115
Cdd:pfam00047   1 SAPPTVTVLEGDSATLTCSASTGSPGPDVTWSKE---GGTLIESLKVKHDNGRTTQSSLL----------ISNVTKEDAG 67

                          90
                  ....*....|....*....
gi 2462580740 116 TYYCVKFRKGSPENVEFKS 134
Cdd:pfam00047  68 TYTCVVNNPGGSATLSTSL 86

Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig) domain of major histocompatibility complex (MHC) class II beta chain. MHC class II molecules play a key role in the initiation of the antigen-specific immune reponse. These molecules have been shown to be expressed constitutively on the cell surface of professional antigen-presenting cells (APCs), including B-lymphocytes, monocytes, and macrophages in both humans and mice. The expression of these molecules has been shown to be induced in nonprofessional APCs such as keratinocyctes and they are also expressed on the surface of activated human T cells and on T cells from other species. The MHC II molecules present antigenic peptides to CD4(+) T-lymphocytes. These peptides derive mostly from proteolytic processing via the endocytic pathway of antigens internalized by the APC. These peptides bind to the MHC class II molecules in the endosome before they are transported to the cell surface. MHC class II molecules are heterodimers, comprised of two similarly-sized membrane-spanning chains, alpha and beta. Each chain has two globular domains (N- and C-terminal) and a membrane-anchoring transmembrane segment. The two chains form a compact four-domain structure. The peptide-binding site is a cleft in the structure.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 160 PEHTVSFTCESHGFSPRDITLKWFKNGNEL------SDFQTNVDPTGQSVaysirstarVVLD----PWDVRSqviCEVA 229
Cdd:cd05766    16 LEHPNLLVCSVTGFYPAEIEVKWFRNGQEEtagvvsTELIPNGDWTFQIL---------VMLEttprRGDVYT---CQVE 83

                          90
                  ....*....|
gi 2462580740 230 HVTLQgDPLR 239
Cdd:cd05766    84 HSSLQ-SPLT 92

Immunoglobulin light chain Constant domain; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig) light chain constant (C) domain. 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. There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determine the type of immunoglobulin: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which seem to be functionally identical, and can associate with any of the heavy chains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 148 APVVL--GPAARTTPEHTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPTGQS-VAYSIRSTARVVLDPWDVRSQV 224
Cdd:cd07699     1 APSVTifPPSSEELSSGKATLVCLINKFYPGFATVTWKVDGSTVSSGVTTSKTEQQSdNTYSMSSYLTLSSSDWNKHKVY 80

                  ....*....
gi 2462580740 225 ICEVAHVTL 233
Cdd:cd07699    81 TCEVTHEGL 89

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 2462580740  39 KLLLVTVGKTATLHCTVTSLLPVG---PVLW-FRGVGPGREL---------IYNQKEGHFP-RVTTVSDLTKRnnmDFSI 104
Cdd:cd05715     7 RELNVLNGSDVRLTCTFTSCYTVGdafSVTWtYQPEGGNTTEsmfhyskgkPYILKVGRFKdRVSWAGNPSKK---DASI 83

                          90
                  ....*....|....*
gi 2462580740 105 RISSITPADVGTYYC 119
Cdd:cd05715    84 VISNLQFSDNGTYTC 98

Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain of histocompatibility antigen (HLA) DM; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain of histocompatibility antigen (HLA) DM. Human HLA-DM plays a critical role in antigen presentation to CD4 T cells by catalyzing the exchange of peptides bound to MHC class II molecules. Type 1 diabetes is correlated with DM activation and it is also implicated in viral infections such as herpes simplex virus, celiac disease, multiple sclerosis, other autoimmune diseases, and leukemia. MHC class II molecules play a key role in the initiation of the antigen-specific immune reponse. These molecules have been shown to be expressed constitutively on the cell surface of professional antigen-presenting cells (APCs), including B-lymphocytes, monocytes, and macrophages in both humans and mice. The expression of these molecules has been shown to be induced in nonprofessional APCs such as keratinocyctes, and they are expressed on the surface of activated human T cells and on T cells from other species. The MHC II molecules present antigenic peptides to CD4(+) T-lymphocytes. These peptides derive mostly from proteolytic processing via the endocytic pathway, of antigens internalized by the APC. These peptides bind to the MHC class II molecules in the endosome before they are transported to the cell surface. MHC class II molecules are heterodimers, comprised of two similarly-sized membrane-spanning chains, alpha and beta. Each chain had two globular domains (N- and C-terminal), and a membrane-anchoring transmembrane segment. The two chains form a compact four-domain structure. The peptide-binding site is a cleft in the structure.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 156 ARTTPEHT---VSFTCESHGFSPRDITLKWFKNGNELSDF-------QTNVDPTgqsvaYSIRSTARVVLDPWDVRSqvi 225
Cdd:cd21002     9 APTTPFNTrepVMLACHVWGFYPADVTITWLKNGDPVAPHssapktaQPNGDWT-----YQTQVTLAVTPSPGDTYT--- 80

                          90
                  ....*....|....
gi 2462580740 226 CEVAHVTLQgDPLR 239
Cdd:cd21002    81 CSVQHASLP-EPLL 93

Immunoglobulin domain of Cluster of Differentiation (CD) 1; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin domain of Cluster of Differentiation (CD) 1. CD1 family of transmembrane glycoproteins, are structurally related to the major histocompatibility complex (MHC) proteins and form heterodimers with beta-2-microglobulin. They mediate the presentation of primarily lipid and glycolipid antigens of self or microbial origin to T cells. The human genome contains five CD1 family genes (CD1a, CD1b, CD1c, CD1d, and CD1e) organized in a cluster on chromosome 1. The CD1 family members are thought to differ in their cellular localization and specificity for particular lipid ligands. CD1a localizes to the plasma membrane and to recycling vesicles of the early endocytic system. Alternative splicing results in multiple transcript variants. Immunoglobulin (Ig) domain of major histocompatibility complex (MHC) class I alpha chain. Class I MHC proteins bind antigenic peptide fragments and present them to CD8+ T lymphocytes. Class I molecules consist of a transmembrane alpha chain and a small chain called the beta-2-microglobulin. The alpha chain contains three extracellular domains, two of which fold together to form the peptide-binding cleft (alpha1 and alpha2), and one which has an Ig fold (alpha3). Peptide binding to class I molecules occurs in the endoplasmic reticulum (ER) and involves both chaperones and dedicated factors to assist in peptide loading. Class I MHC molecules are expressed on most nucleated cells. C1-set Ig domains have one beta sheet that is formed by strands A, B, E, and D and the other strands by G, F, C, and C'.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 145 KPSAPVVLGPAArtTPEHTvSFTCESHGFSPRDITLKWFKNGNELSD------FQTNVDPTgqsvaYSIRSTARVVLDPw 218
Cdd:cd21029     2 KPRVRLSSRPSP--GDGHL-QLSCHVTGFYPRPIEVTWLRDGQEQMDgtqsggILPNHDGT-----YQLRKTLDIAPGE- 72

                          90
                  ....*....|....*...
gi 2462580740 219 dvRSQVICEVAHVTLQGD 236
Cdd:cd21029    73 --GAGYSCRVDHSSLKQD 88

First immunoglobulin variable (IgV) domain of poliovirus receptor (PVR, also known as CD155 and necl-5), and similar domains; The members here are composed of the first immunoglobulin (Ig) domain of poliovirus receptor (PVR, also known as CD155 and nectin-like protein 5 (necl-5)). 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), that result from alternate splicing of the CD155 mRNA, and have identical extracellular domains. CD155-beta and CD155-gamma are secreted; 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" with a footprint similar to that of the intercellular adhesion molecule-1 receptor on human rhinoviruses. This group also includes the first Ig-like domain of nectin-1 (also known as poliovirus receptor related protein(PVRL)1; CD111), nectin-3 (also known as PVRL 3), nectin-4 (also known as PVRL4; LNIR receptor)and DNAX accessory molecule 1 (DNAM-1; CD226).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740  44 TVGKTATLHCTVTSLLP--VGPVLWFRGVGPGRELI--YNQKEG-HFP-----RVTTVSDLTKRNNMdfSIRISSITPAD 113
Cdd:cd05718    12 FLGGSVTLPCSLTSPGTtkITQVTWMKIGAGSSQNVavFHPQYGpSVPnpyaeRVEFLAARLGLRNA--TLRIRNLRVED 89

                          90
                  ....*....|....*
gi 2462580740 114 VGTYYC--VKFRKGS 126
Cdd:cd05718    90 EGNYICefATFPQGN 104

CH1 domain (first constant Ig domain of the heavy chain) in immunoglobulin heavy alpha, delta, epsilon, gamma, and mu chains; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the first immunoglobulin constant-1 set domain of alpha, delta, epsilon, gamma, and mu heavy chains. This domain is found on the Fab antigen-binding fragment. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda; each is composed of a constant domain and a variable domain. There are five types of heavy chains: alpha, delta, epsilon, gamma, and mu, all consisting of a variable domain (VH) with three (alpha, delta and gamma) or four (epsilon and mu) constant domains (CH1 to CH4). Ig molecules are modular proteins, in which the variable and constant domains have clear, conserved sequence patterns. This group belongs to the C1-set of IgSF domains, which are classical Ig-like domains resembling the antibody constant domain. C1-set domains are found almost exclusively in molecules involved in the immune system, such as in immunoglobulin light and heavy chains, in the major histocompatibility complex (MHC) class I and II complex molecules, and in various T-cell receptors.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 148 APVV--LGPAARTTPEHTVSFTCESHGFSPRDITLKWFKNGN-ELSDFQTNVDPTGQSVA-YSIRSTARVVLDPWDVRSQ 223
Cdd:cd04985     1 APTVfpLQSATKSQSNGPVALGCLISDYFPESITVSWQKNTNsITSGFTRTFPVVLRSGGdYSCSSQLTVPLQEWNSGEV 80

                  ....*..
gi 2462580740 224 VICEVAH 230
Cdd:cd04985    81 YKCQVQH 87

Class Ia major histocompatibility complex (MHC) immunoglobulin domain of RT1-Aa; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class Ia major histocompatibility complex (MHC) immunoglobulin domain of RT1-Aa. While most mammalian species transport these peptides into the ER via a single allele of TAP, rats have evolved different TAPs, TAP-A and TAP-B, RT1-Aa and RT1-A1c, which are associated with TAP-A and TAP-B. The rat MHC class Ia molecule RT1-Aa has the unusual capacity to bind long peptides ending in arginine, such as MTF-E, a thirteen-residue, maternally transmitted minor histocompatibility antigen. Class I MHC proteins bind antigenic peptide fragments and present them to CD8+ T lymphocytes. Class I molecules consist of a transmembrane alpha chain and a small chain called the beta-2-microglobulin. The alpha chain contains three extracellular domains, two of which fold together to form the peptide-binding cleft (alpha1 and alpha2), and one which has an Ig fold (alpha3). Peptide binding to class I molecules occurs in the endoplasmic reticulum (ER) and involves both chaperones and dedicated factors to assist in peptide loading. Class I MHC molecules are expressed on most nucleated cells.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740 146 PSAPVVLGPaartTPEHTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVD--PTGQSvaySIRSTARVVLdPWDVRSQ 223
Cdd:cd21015     5 PEAHVTLHP----RPEGDVTLRCWALGFYPADITLTWQLNGEDLTQDMELVEtrPAGDG---TFQKWASVVV-PLGKEQN 76

                  ....*..
gi 2462580740 224 VICEVAH 230
Cdd:cd21015    77 YTCRVEH 83

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462580740  43 VTVGKTATLHCTVTSllpvGP---VLWFRGvgpgRELIYNQKEGHFPRVTTVSDLTkrnnmdfsirISSITPADVGTYYC 119
Cdd:pfam13927  13 VREGETVTLTCEATG----SPpptITWYKN----GEPISSGSTRSRSLSGSNSTLT----------ISNVTRSDAGTYTC 74

                  .
gi 2462580740 120 V 120
Cdd:pfam13927  75 V 75

Immunoglobulin (Ig) variable (V) domain of T-cell receptor (TCR) gamma chain; The members here are composed of the immunoglobulin (Ig) variable (V) domain of the gamma chain of gamma/delta T-cell receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are heterodimers consisting of alpha and beta chains or gamma and delta chains. Each chain contains a variable (V) and a constant (C) region. The majority of T cells contain alpha/beta TCRs, but a small subset contain gamma/delta TCRs. Alpha/beta TCRs recognize antigens as peptide fragments presented by major histocompatibility complex (MHC) molecules. Gamma/delta TCRs recognize intact protein antigens directly without antigen processing and recognize MHC independently of the bound peptide. Gamma/delta T cells can also be stimulated by non-peptide antigens such as small phosphate- or amine-containing compounds. The variable domain of gamma/delta TCRs is responsible for antigen recognition and is located at the N-terminus of the receptor. Members of this group contain the standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

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gi 2462580740  36 QPEKLLLVTVGKTATLHCTVTSL-LPVGPVLWFR---GVGPGReLIY------NQKEGHFPRVTTVSDLTKRNNMdFSIR 105
Cdd:cd04982     3 QPQLSITREESKSVTISCKVSGIdFSTTYIHWYRqkpGQALER-LLYvsstsaVRKDSGKTKNKFEARKDVGKST-STLT 80

                          90       100
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gi 2462580740 106 ISSITPADVGTYYCVKFRKGS 126
Cdd:cd04982    81 ITNLEKEDSATYYCAYWESGS 101

Class Ib major histocompatibility complex (MHC) immunoglobulin domain of T10, T22, and similar proteins; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class Ib major histocompatibility complex (MHC) immunoglobulin domain of the murine H-2T-encoded T10, T22, and similar proteins. T10 and T22 are highly related nonclassical major histocompatibility complex (MHC) class Ib proteins that bind to certain gammadelta T cell receptors (TCRs) in the absence of other components. Classical MHC class I (class Ia) molecules participate in immune responses by presenting peptide antigens to cytolytic alpha beta T cells. Many nonclassical MHC class I (class Ib) molecules have distinct antigen-binding capabilities, suggesting that they have evolved for specific tasks that are distinct from those of MHC class Ia. Members of the IgC 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.

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gi 2462580740 154 PAARTT----PEHTVSFTCESHGFSPRDITLKWFKNGNELS 190
Cdd:cd21016     6 PKAHVTrhprPEGDVTLRCWALGFYPADITLTWQKDGEELT 46

CH1 domain (first constant Ig domain of the heavy chain) in immunoglobulin heavy mu chain; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the first immunoglobulin constant-1 set domain of mu chains. It belongs to a family composed of the first immunoglobulin constant-1 set domain of alpha, delta, epsilon, gamma, and mu heavy chains. This domain is found on the Fab antigen-binding fragment. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda; each is composed of a constant domain and a variable domain. There are five types of heavy chains: alpha, delta, epsilon, gamma, and mu, all consisting of a variable domain (VH) with three (alpha, delta and gamma) or four (epsilon and mu) constant domains (CH1 to CH4). Ig molecules are modular proteins, in which the variable and constant domains have clear, conserved sequence patterns. This group belongs to the C1-set of IgSF domains, which are classical Ig-like domains resembling the antibody constant domain. C1-set domains are found almost exclusively in molecules involved in the immune system, such as in immunoglobulin light and heavy chains, in the major histocompatibility complex (MHC) class I and II complex molecules, and in various T-cell receptors.

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gi 2462580740 163 TVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPTGQSVAYSIRSTARVVLDPWDVRSQVICEVAH 230
Cdd:cd21819    17 PVTVGCLATDFLPDSITFSWTDDNNSLTTGVKTYPSVLTGGTYTASSQLQVPESEWKSKENFYCKVEH 84