A Role for Calreticulin in the Clearance of Apoptotic Cells and in the Innate Immune System

Abstract

Calreticulin has been shown to bind the collagenous tails of members of the collectin family of pattern recognition molecules. Its presence on cell surfaces then, implies a potential role for recognition of the collectins, and anything they may have bound via their globular head groups. In addition to foreign organisms, collectins bind to apoptotic cells and can mediate their uptake into phagocytic cells via this calreticulin-mediated recognition of the collagenous domains. As a non-transmembrane protein, calreticulin cannot transduce intracellular signals by itself but appears to use for this uptake and removal, a partner, CD91, which does exhibit appropriate intracellular signaling domains and function.