anti-Calreticulin (human), mAb (CR213-2AG)

Calreticulin is involved in regulation of intracellular Ca2+ homoeostasis and ER Ca2+ capacity. It constitutes together with calnexin and ERp57 the 'calreticulin/calnexin cycle' that is responsible for folding and quality control of newly synthesized glycoproteins. Calreticulin has been implicated to play a role in many biological systems, including functions inside and outside the ER, indicating that the protein is a multi-process molecule. Recently, calreticulin has been identified as an endogenous ligand of the NK cell receptor NKp46. NKp46 recognizes externalized calreticulin (ecto-CRT), which translocates from the endoplasmic reticulum (ER) to the cell membrane during ER stress. ER stress and ecto-CRT are hallmarks of chemotherapy-induced immunogenic cell death, favivirus infection and senescence. NKp46-mediated killing is inhibited by knockout or knockdown of CALR, the gene encoding CRT, or CRT antibodies, and is enhanced by ectopic expression of glycosylphosphatidylinositol-anchored CRT. NKp46 recognition of ecto-CRT as a danger-associated molecular pattern eliminates ER-stressed cells.