Human NKG2H (NK cell Group 2 isoform H; also NK cell receptor H) is a 38 kDa member of the C-type lectin-like domain superfamily of molecules. It represents an alternative splice form of the NKG2E/KLRC3 gene, one of three related genes on human Ch12 that give rise to five isoform variants (NKG2A & B, C, E & H). NKG2H is present on both NK and CD8+ T cells as a 70 kDa disulfide-linked heterodimer with CD94. It serves as a receptor for HLA-E (Qa-1b in mice), an MHC-I like molecule that largely presents fragments of signal peptides associated with classical MHC-I molecules. When engaged, NKG2H is potentially activating, and perhaps will initiate cytolysis and cytokine production. Alternatively, it has been suggested that NKG2H is involved in monitoring the physiological state of its target cell, presumably through the detection of increased levels of HLA-E. In either case, this activity is likely to be context-dependent, as the related NK2GA and B isoforms are inhibitory in nature, and compete for the same target. NKG2H is a 257 amino acid (aa) type II transmembrane glycoprotein. It contains a 70 aa cytoplasmic segment coupled to a 164 aa extracellular region (aa 94-257) that possesses a 108 aa C-type lectin domain (aa 117-224). NKG2H is the long isoform of the KLRC3 gene (SwissProt #:Q07444). The short form (NKG2E) is 240 aa in length, and diverges from the long form beginning at Val227 where 14 aa substitute for aa 227-257 of the long form. Over aa 241-253, human NKG2H shares no meaningful sequence identity with any other NKG2 isoforms or rodent species orthologs.
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| Product By Gene ID | 3823 |
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