MHC class I polypeptide-related sequence A

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Available structures
PDB Human UniProt search: PDBe RCSB
Aliases MICA, MIC-A, PERB11.1, MHC class I polypeptide-related sequence A
External IDs GeneCards: 100507436
Genetically Related Diseases
Disease Name References
Rheumatoid Arthritis
RNA expression pattern
PBB GE MICA 205904 at tn.png

PBB GE MICA 205905 s at tn.png
More reference expression data
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 6: 31.4 – 31.42 Mb n/a
PubMed search [2] n/a
View/Edit Human

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[edit]


  1. ^ a b 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. ^ a b 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. ^ a b 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[edit]