Second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs). Interactions between IgG and FcgammaR are important to the initiation of cellular and humoral response. IgG binding to FcgammaR leads to a cascade of signals and ultimately to functions such as antibody-dependent-cellular-cytotoxicity (ADCC), endocytosis, phagocytosis, release of inflammatory mediators, etc. FcgammaR has two Ig-like domains. This group also contains FcepsilonRI which binds IgE with high affinity.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1659411145  84 ILRAvPSAEPQAGSPMTLSCQ--TKLPLQRSAarllfsFYKDGRIVQSRGLSSEFQIPTASEDHSGSYWCEA 153
Cdd:cd05753     3 LLQA-PSAVVFEGEPLTLRCHgwKDKKVHKVT------YYKDGKALKFSYENSNFSIPQATLSDSGSYHCSG 67

Second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs). Interactions between IgG and FcgammaR are important to the initiation of cellular and humoral response. IgG binding to FcgammaR leads to a cascade of signals and ultimately to functions such as antibody-dependent-cellular-cytotoxicity (ADCC), endocytosis, phagocytosis, release of inflammatory mediators, etc. FcgammaR has two Ig-like domains. This group also contains FcepsilonRI which binds IgE with high affinity.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1659411145  84 ILRAvPSAEPQAGSPMTLSCQ--TKLPLQRSAarllfsFYKDGRIVQSRGLSSEFQIPTASEDHSGSYWCEA 153
Cdd:cd05753     3 LLQA-PSAVVFEGEPLTLRCHgwKDKKVHKVT------YYKDGKALKFSYENSNFSIPQATLSDSGSYHCSG 67

Second immunoglobulin (Ig)-like domain found in Leukocyte Ig-like receptors, Natural killer inhibitory receptors (KIRs) and similar domains; member of Immunoglobulin Constant-2 set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain found in Leukocyte Ig-like receptors (LILRs), Natural killer inhibitory receptors (KIRs, also known as also known as cluster of differentiation (CD) 158), and similar proteins. This group includes LILRB1 (also known as LIR-1), LILRA5 (also known as LIR9), an activating natural cytotoxicity receptor NKp46, the immune-type receptor glycoprotein VI (GPVI), and the IgA-specific receptor Fc-alphaRI (also known as cluster of differentiation (CD) 89). LILRs are a family of immunoreceptors expressed on expressed on T and B cells, on monocytes, dendritic cells, and subgroups of natural killer (NK) cells. The human LILR family contains nine proteins (LILRA1-3, and 5, and LILRB1-5). From functional assays, and as the cytoplasmic domains of various LILRs, for example LILRB1, LILRB2 (also known as LIR-2), and LILRB3 (also known as LIR-3) contain immunoreceptor tyrosine-based inhibitory motifs (ITIMs), it is thought that LIR proteins are inhibitory receptors. Of the eight LIR family proteins, only LILRB1, and LILRB2, show detectable binding to class I MHC molecules; ligands for the other members have yet to be determined. The extracellular portions of the different LIR proteins contain different numbers of Ig-like domains for example, four in the case of LILRB1, and LILRB2, and two in the case of LILRB4 (also known as LIR-5). The activating natural cytotoxicity receptor NKp46 is expressed in natural killer cells, and is organized as an extracellular portion having two Ig-like extracellular domains, a transmembrane domain, and a small cytoplasmic portion. GPVI, which also contains two Ig-like domains, participates in the processes of collagen-mediated platelet activation and arterial thrombus formation. Fc-alphaRI is expressed on monocytes, eosinophils, neutrophils, and macrophages; it mediates IgA-induced immune effector responses such as phagocytosis, antibody-dependent cell-mediated cytotoxicity and respiratory burst. Killer cell immunoglobulin-like receptors (KIRs; also known as CD158 for human KIR) are transmembrane glycoproteins expressed by natural killer cells and subsets of T cells. KIRs are a family of highly polymorphic activating and inhibitory receptors that serve as key regulators of human NK cell function. The KIR proteins are classified by the number of extracellular immunoglobulin domains (2D or 3D) and by whether they have a long (L) or short (S) cytoplasmic domain. KIR proteins with the long cytoplasmic domain transduce inhibitory signals upon ligand binding via an immune tyrosine-based inhibitory motif (ITIM), while KIR proteins with the short cytoplasmic domain lack the ITIM motif and instead associate with the TYRO protein tyrosine kinase binding protein to transduce activating signals. The major ligands for KIR are MHC class I (HLA-A, -B or -C) molecules.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1659411145  83 PILRAVPSAEPQAGSPMTLSCQTKLPLQRsaarllFSFYKDGR----IVQSRGLSSEFQIPTASEDHSGSYWC 151
Cdd:cd05711     2 PFLSAHPGPVVPSGENVTLQCHSRIGFDR------FILYKEGRspllQFHGSGFQASFPLGPVTPAHAGTYRC 68

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.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1659411145  87 AVPSAEPQAGSPMTLSCQTKLplQRSAARLLFSFYKDGRIVQSRGL-------SSEFQIPTASEDHSGSYWCEAATEDNQ 159
Cdd:pfam00047   2 APPTVTVLEGDSATLTCSAST--GSPGPDVTWSKEGGTLIESLKVKhdngrttQSSLLISNVTKEDAGTYTCVVNNPGGS 79

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gi 1659411145 160 V 160
Cdd:pfam00047  80 A 80