Calreticulin is an endoplasmic reticulum Ca(2+) binding chaperone that has multiple functions inside and outside of the endoplasmic reticulum. It is involved in the quality control of newly synthesized proteins and glycoproteins, interacting with various other endoplasmic reticulum chaperones, specifically calnexin and ER protein of 57-kDa in the calreticulin/calnexin cycle. Calreticulin also plays a crucial role in regulating intracellular Ca(2+) homeostasis, associating calreticulin with a wide variety of signaling processes, such as cardiogenesis, adipocyte differentiation and cellular stress responses. The role of calreticulin outside of the endoplasmic reticulum is also extensive, including functions in wound healing and immunity. Therefore, calreticulin has important implications in health and disease. Signaling facts.