Complement Component C3 Is Highly Expressed in Human Pancreatic Islets and Prevents β Cell Death via ATG16L1 Interaction and Autophagy Regulation

？ Islet C3 expression is upregulated in human T2D and rodent models of diabetes ？ C3 is present within the cytosol and binds autophagy-related protein 16-1 (ATG16L1) ？ β cells lacking C3 have impaired autophagy ？ Intracellular C3 protects β cells from palmitic acid/IAPP-mediated apoptosi