Control of protein translation by IPR-mediated Ca release in Drosophila neuroendocrine cells.

The inositol 1,4,5-trisphosphate receptor (IPR) is one of two Ca channels that gates Ca release from ER-stores. The ligand IP, generated upon specific G-protein coupled receptor activation, binds to IPR to release Ca into the cytosol. IPR also mediates ER-store Ca release into the mitochondria, under basal as well as stimulatory conditions; an activity that influences cellular bioenergetics and thus, cellular growth and proliferation. In Drosophila neuroendocrine cells expressing a hypomorphic mutant of IPR, we observed reduced protein translation levels. Here, we discuss the possible molecular mechanism for this observation. We hypothesise that the cellular energy sensor, AMPK connects IPR mediated Ca release into the mitochondria, to protein translation, via the TOR pathway.