5-IP is a GPCR messenger mediating neural control of synaptotagmin-dependent insulin exocytosis and glucose homeostasis.

5-diphosphoinositol pentakisphosphate (5-IP) is a signalling metabolite linked to various cellular processes. How extracellular stimuli elicit 5-IP signalling remains unclear. Here we show that 5-IP in β cells mediates parasympathetic stimulation of synaptotagmin-7 (Syt7)-dependent insulin release.