MICA Q29983

MHC I类多肽相关序列A (MIC-A)

功能描述

广泛表达的膜结合蛋白，作为配体刺激激活受体KLRK1/NKG2D，该受体表达于几乎所有人类自然杀伤(NK)细胞、γδ T细胞和CD8 αβ T细胞表面 (PubMed:11491531, PubMed:11777960)。在应激条件下（如病毒和细菌感染或DNA损伤反应）表达上调，作为细胞应激信号，MICA与KLRK1/NKG2D的结合触发NK细胞，导致一系列免疫效应功能，如细胞毒性和细胞因子产生 (PubMed:10426993)。 {ECO:0000269|PubMed:10426993, ECO:0000269|PubMed:11224526, ECO:0000269|PubMed:11491531, ECO:0000269|PubMed:11777960, ECO:0000269|PubMed:9497295}。

组织特异性

Widely expressed with the exception of the central nervous system where it is absent. Expressed predominantly in gastric epithelium and also in monocytes, keratinocytes, endothelial cells, fibroblasts and in the outer layer of Hassal's corpuscles within the medulla of normal thymus. In skin, expressed mainly in the keratin layers, basal cells, ducts and follicles. Also expressed in many, but not all, epithelial tumors of lung, breast, kidney, ovary, prostate and colon. In thyomas, overexpressed in cortical and medullar epithelial cells. Tumors expressing MICA display increased levels of gamma delta T-cells.

亚细胞定位

Cell membrane