The primary chaperone of the endoplasmic reticulum, the most abundant protein in microsomal preparations from mammalian cells, and one of the hsp90 family of heat shock proteins. A glycoprotein (tumour rejection antigen gp96, TRA1, glucose-regulated protein, grp94, 803 aa) with calcium-binding properties that acts as a natural adjuvant by stimulating antigen-presenting cells to express cytokines. In the adaptive immune response endoplasmin has peptide-binding activity and a role in antigen presentation. It is also important in embryonic development, probably through an involvement with the production of insulin-like growth factors.
Subjects: Medicine and Health.