Golgi-Resident G alpha o Promotes Protrusive Membrane Dynamics

摘要

To form protrusions like neurites, cells must coordinate their induction and growth. The first requires cytoskeletal rearrangements at the plasma membrane (PM), the second requires directed material delivery from cell's insides. We find that the G alpha o-subunit of heterotrimeric G proteins localizes dually to PM and Golgi across phyla and cell types. The PM pool of G alpha o induces, and the Golgi pool feeds, the growing protrusions by stimulated trafficking. Golgi-residing KDELR binds and activates monomeric G alpha o, atypically for G protein-coupled receptors that normally act on heterotrimeric G proteins. Through multidimensional screenings identifying > 250 G alpha o interactors, we pinpoint several basic cellular activities, including vesicular trafficking, as being regulated by G alpha o. We further find small Golgi-residing GTPases Rab1 and Rab3 as direct effectors of G alpha o. This KDELR -> G alpha o -> Rab1/3 signaling axis is conserved from insects to mammals and controls material delivery from Golgi to PM in various cells and tissues.