TBC1D4 and type 2 diabetes mellitus: To mimic the situation in T2D, FOXP1, TBC1D4, RHOT1, and CABLES1 were silenced in human islets using siRNA (Fig. 4e), resulting in reduced glucose-stimulated insulin secretion (GSIS) (Fig. 4f) without changing the insulin content (Supplementary Fig. 5a).