A collaboration between the labs of Colin Taylor and Eugene Brailoiu (Temple University, Philadelphia) has identified a new messenger linking receptors in the plasma membrane to release of calcium from intracellular stores...
All cells talk to each other, detecting extracellular signals through receptors expressed in the plasma membrane. It is often the membrane itself that is metabolized to produce the intracellular signals that relay information from receptors to intracellular targets. IP3 is one product of this metabolism, and it causes release of calcium from intracellular stores. Work published in Cell Reports shows that receptors that stimulate IP3 formation also stimulate breakdown of another lipid, phosphatidylcholine. The choline produced by this reaction has hitherto been thought to be a by-product, but the new results show that choline works alongside IP3 to promote calcium release. Choline binds to a much studied protein, the sigma 1 receptor, which then enhances the calcium release evoked by IP3.
Brailoiu, E, Chakraborty, S....... Taylor, CW (2019) Choline is an intracellular messenger linking extracellular stimuli to IP3-evoked Ca2+ signals through sigma-1 receptors. Cell Reports 26, 330-337.