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

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 beta gamma 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 beta 1 gamma 2 and beta 3 gamma 2 via the Golgi apparatus-associated PKC eta. Compromising the kinase activity of PKC eta-inhibited protein transport from TGN to the cell surface. Expression of constitutively activated PKC eta caused Golgi fragmentation, which was inhibited by a kinase inactive form of PKD. Our findings reveal that beta gamma, PKC eta, and PKD act in series to generate transport carriers from the TGN and their overactivation results in complete vesiculation of the Golgi apparatus.