Islet antigen-2 (IA-2) is an autoantigen in type 1 diabetes and plays a role in insulin secretion. IA-2 is found in dense-core secretory vesicles and interacts with the product of this gene, a sorting nexin. In mouse pancreatic beta-cells, the encoded protein influenced insulin secretion by stabilizing the number of dense-core secretory vesicles. [provided by RefSeq, Dec 2016].