Calreticulin, a multifunctional Ca2+ binding chaperone of the endoplasmic reticulum

Calreticulin is a ubiquitous endoplasmic reticulum Ca2+ binding chaperone. The protein has been implicated in a variety of diverse functions. Calretic ulin is a lectin-like chaperone and, together with calnexin, it plays an im portant role in quality control during protein synthesis, folding, and post translational modification. Calreticulin binds Ca2+ and affects cellular Ca 2+ homeostasis. The protein increases the Ca2+ storage capacity of the endo plasmic reticulum and modulates the function of endoplasmic reticulum Ca2+- ATPase. Calreticulin also plays a role in the control of cell adhesion and steroid-sensitive gene expression. Recently, the protein has been identifie d and characterized in higher plants but its precise role in plant cells aw aits further investigation.