MHC class I polypeptide-related sequence A(MICA) is a cell surface glycoprotein encoded by the MICAgene located within MHC locus.[1] MICA is related to MHC class I and has similar domain structure, which is made up of external α1α2α3 domain, transmembrane segment and C-terminal cytoplasmic tail.[1] However, MICA is not associated with β2-microglobulin nor binds peptides as conventional MHC class I molecules do.[2] MICA rather functions as a stress-induced ligand for NKG2D receptor.[3] For example, the heat shock stress pathway is involved in the regulation of MICA expression as transcription of MICA is regulated by promoter heat shock element.[2] MICA is broadly recognized by NK cells, γδ T cells, and CD8+ αβ T cells which carry NKG2D receptor on their cell surface. As a result of NKG2D-MICA engagement, effector cytolytic responses of T cells and NK cells against epithelial tumor cells expressing MICA are initiated.[3]
↑ 3.03.1Bauer S, Groh V, Wu J, Steinle A, Phillips JH, Lanier LL, Spies T (Jul 1999). "Activation of NK cells and T cells by NKG2D, a receptor for stress-inducible MICA". Science. 285 (5428): 727–9. doi:10.1126/science.285.5428.727. PMID10426993.
Blumberg RS (Feb 1998). "Current concepts in mucosal immunity. II. One size fits all: nonclassical MHC molecules fulfill multiple roles in epithelial cell function". The American Journal of Physiology. 274 (2 Pt 1): G227–31. PMID9486173.
