MHC Class I Polypeptide Related Sequence A (MICA)

MICA encodes the higly polymorphic MHC (HLA) class I chain-related gene A. The protein product is expressed on the cell surface, although unlike canonical class I molecules does not seem to associate with beta-2-microglobulin. It is thought that MICA functions as a stress-induced antigen that is broadly recognized by intestinal epithelial gamma delta T cells. Alternative splicing results in multiple transcript variants.The MICA gene encodes a 383-amino acid polypeptide with a predicted mass of 43 kD. It is further distinguished by its unusual exon-intron organization and preferential expression in fibroblasts and epithelial cells. However, the presence of distinctive residues in the MICA amino acid sequence translated from cDNA suggested that the putative MICA chain folds similarly to typical class I chains and may have the capacity to bind peptide or other short ligands.