Protein kinase D regulates the fission of cell surface destined transport carriers from the trans-Golgi network.

When a kinase inactive form of Protein Kinase D (PKD-K618N) was expressed in HeLa cells, it localized to the trans-Golgi network (TGN) and caused extensive tubulation. Cargo that was destined for the plasma membrane was found in PKD-K618N-containing tubes but the tubes did not detach from the TGN. As a result, the transfer of cargo from TGN to the plasma membrane was inhibited. We have also demonstrated the formation and subsequent detachment of cargo-containing tubes from the TGN in cells stably expressing low levels of PKD-K618N. Our results suggest that PKD regulates the fission from the TGN of transport carriers that are en route to the cell surface.