MAPK1 and type 1 diabetes mellitus: We found that MAPK1, but not RELA, was significantly reduced in the α cells of donors with type 1 diabetes (vs. control and autoantibody-positive donors; Fig. 4D, shown in Fig. 4E–G), whereas JAK1 was expressed at insignificant levels within the islets in all groups (Fig. 4E–G).