PKCη is required for β1γ2/β3γ2- and PKD-mediated transport to the cell surface and the organization of the Golgi apparatus

Abstract

Protein kinase D (PKD) binds to a pool of diacylglycerol (DAG) in the TGN and undergoes a process of activation that involves heterotrimeric GTP-binding protein subunits βγ to regulate membrane fission. This fission reaction is used to generate transport carriers at the TGN that are en route to the cell surface. We now report that PKD is activated specifically by G protein subunit β1γ2 and β3γ2 via the Golgi apparatus–associated PKCη. Compromising the kinase activity of PKCη-inhibited protein transport from TGN to the cell surface. Expression of constitutively activated PKCη caused Golgi fragmentation, which was inhibited by a kinase inactive form of PKD. Our findings reveal that βγ, PKCη, and PKD act in series to generate transport carriers from the TGN and their overactivation results in complete vesiculation of the Golgi apparatus.