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 i n HeLa cells, it localized to the trans-Golgi network (TGN) and caused exte nsive 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. A s a result, the transfer of cargo from TGN to the plasma membrane was inhib ited. We have also demonstrated the formation and subsequent detachment of cargo-containing tubes from the TGN in cells stably expressing low levels o f PKD-K618N. Our results suggest that PKD regulates the fission from the TG N of transport carriers that are en route to the cell surface.