PTPRN and diabetes mellitus: Other insulin granule-associated genes previously identified by proteomic studies [46] and upregulated in the KK/HlJ mice pancreata included key pro-IAPP processing enzyme PCSK2, together with the diabetes islet cell autoantigen Protein tyrosine phosphatase receptor type N (PTPRN, IA-2), Synaptosomal-Associated Protein SNAP25, Synaptotagamin SYT5, Chromogranin CHGB, Secretogranins SCG2 and SCG3, the Staninocalcin STC2, and the outward rectifying potassium channel KCNK16.