8.A.165.1.2
Calreticulin (CRT) of 417 aas and one N-terminal TMS. Calreticulin is a sugar-binding protein chaparone (a lectin-like chaperone) that functions in peptide-loading to the major histocompatibility complex encoded class I (MHC-I) molecules (Margulies et al. 2020). The uterine sacroplasmic reticulum (SR) takes up and stores calcium [Ca], using the SERCA ATPase and the Ca-buffering proteins, calsequestrin and calreticulin. This stored Ca can be released via IP(3)-gated Ca channels (Noble et al. 2009), so calreticulin serves as an intermediate between the SERCA ATPase and Ca channels such as IP930-gated channels. The pre-apoptotic translocation of intracellular calreticulin (endo-CRT) to the plasma membrane surface (ecto-CRT) is critical for the recognition and engulfment of dying tumor cells by dendritic cells (Obeid et al. 2007).