GRP may refer to:
Gastrin-releasing peptide, also known as GRP, is a neuropeptide, a regulatory molecule that has been implicated in a number of physiological and pathophysiological processes. Most notably, GRP stimulates the release of Gastrin from the G cells of the stomach.
The gene from which GRP is derived encodes a number of bombesin-like peptides. Its 148-amino acid preproprotein, following cleavage of a signal peptide, is further processed to produce either the 27-amino acid gastrin-releasing peptide or the 10-amino acid neuromedin C. These smaller peptides regulate numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation.
Gastrin-releasing peptide is a regulatory human peptide that elicits gastrin release and regulates gastric acid secretion and enteric motor function. The post-ganglionic fibers of the vagus nerve that innervate the G cells of the stomach release GRP, which stimulates the G cells to release gastrin.
Heat shock protein 90kDa beta member 1 (HSP90B1), known also as endoplasmin, gp96, grp94 and ERp99, is a chaperone protein that in humans is encoded by the HSP90B1 gene.
HSP90B1 is an HSP90 paralogue that is found in the endoplasmic reticulum. It plays critical roles in folding proteins in the secretory pathway such as Toll-like receptors and integrins. It has been implicated as an essential immune chaperone to regulate both innate and adaptive immunity. Tumor-derived HSP90B1 (vitespen) has entered clinical trials for cancer immunotherapy.