TMEM37 and pancreatic insulinoma: Silencing of either Arg2 (ESM Fig. 5a) or Ppp1r1a (ESM Fig. 5b) in insulinoma INS-1 832/13 cells reduced insulin secretion (Fig. 3e, f), while the opposite was observed by silencing Tmem37 (Fig. 3g, ESM Fig. 5c), consistent with the latter being an inhibitory subunit of voltage-gated calcium channels [30].