Augmented glucose-induced insulin release in mice lacking Go2, but not Go1or Gi proteins

Abstract

Insulin secretion by pancreatic β cells is a complex and highly regulated process. Disruption of this process can lead to diabetes mellitus. One of the various pathways involved in the regulation of insulin secretion is the activation of heterotrimeric G proteins. Bordetella pertussis toxin (PTX) promotes insulin secretion, suggesting the involvement of one or more of three Gi and/or two Go proteins as suppressors of insulin secretion from β cells. However, neither the mechanism of this inhibitory modulation of insulin secretion nor the identity of the Gi/o proteins involved has been elucidated. Here we show that one of the two splice variants of Go, Go2, is a key player in the control of glucose-induced insulin secretion by β cells. Mice lacking G o2α, but not those lacking α subunits of either G o1 or any Gi proteins, handle glucose loads more efficiently than wild-type (WT) mice, and do so by increased glucose-induced insulin secretion. We thus provide unique genetic evidence that the G o2 protein is a transducer in an inhibitory pathway that prevents damaging oversecretion of insulin.