Control of p62 binding to TGN38/41 by phosphorylation.

TGN38/41 cycles between the trans-Golgi network (TGN) and plasma membrane, traversing three sorting compartments: the TGN, plasma membrane and early endosome. The targeting signals responsible for this complex itinerary reside in a short cytoplasmic domain of 33 amino acid residues. We show that phosphorylation of the cytoplasmic domain of TGN38 prevents binding of p62--a cytoplasmic protein essential for exocytic vesicle formation. Thus the cycle of TGN38/41 traffic, and by implication the pathway of exocytosis, could be controlled by phosphorylation of the TGN38 cytoplasmic domain.