MHC class I polypeptide-related sequence A

MHC class I polypeptide-related sequence A
PDB rendering based on 1b3j.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 1B3J​, 1HYR​
Identifiers
Symbols	MICA ; MIC-A; PERB11.1
External IDs	OMIM: 600169 MGI: 2179989 HomoloGene: 129888 GeneCards: MICA Gene
Gene ontology Molecular function • protein binding • beta-2-microglobulin binding • natural killer cell lectin-like receptor binding Cellular component • extracellular space • cytoplasm • integral component of plasma membrane • cell surface Biological process • T cell mediated cytotoxicity • immune response to tumor cell • cellular response to DNA damage stimulus • response to heat • viral process • cytolysis • antigen processing and presentation • negative regulation of natural killer cell activation • natural killer cell mediated cytotoxicity • defense response to bacterium • negative regulation of natural killer cell mediated cytotoxicity • gamma-delta T cell activation • defense response to virus Sources: Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	100507436	243864
Ensembl	ENSG00000183214	n/a
UniProt	Q29983	n/a
RefSeq (mRNA)	NM_000247	n/a
RefSeq (protein)	NP_000238	n/a
Location (UCSC)	Chr 6: 31.4 – 31.42 Mb	n/a
PubMed search

MHC class I polypeptide-related sequence A (MICA) is a cell surface glycoprotein encoded by the MICA gene 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]

See also

• MHC class I
• Major histocompatibility complex
• MICB

References

1. Bahram S, Bresnahan M, Geraghty DE, Spies T (Jul 1994). "A second lineage of mammalian major histocompatibility complex class I genes". Proceedings of the National Academy of Sciences of the United States of America 91 (14): 6259–63. doi:10.1073/pnas.91.14.6259. PMC 44180. PMID 8022771.
2. Groh V, Bahram S, Bauer S, Herman A, Beauchamp M, Spies T (Oct 1996). "Cell stress-regulated human major histocompatibility complex class I gene expressed in gastrointestinal epithelium". Proceedings of the National Academy of Sciences of the United States of America 93 (22): 12445–50. doi:10.1073/pnas.93.22.12445. PMC 38011. PMID 8901601.
3. Bauer 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. PMID 10426993.

Further reading

• Klein J, O'hUigin C (Jul 1994). "The conundrum of nonclassical major histocompatibility complex genes". Proceedings of the National Academy of Sciences of the United States of America 91 (14): 6251–2. doi:10.1073/pnas.91.14.6251. PMC 44177. PMID 8022769.
• Bahram S, Spies T (Jun 1996). "The MIC gene family". Research in Immunology 147 (5): 328–33. doi:10.1016/0923-2494(96)89646-5. PMID 8876061.
• 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. PMID 9486173.