Localization of TGN38 to the trans-Golgi network: involvement of a cytoplasmic tyrosine-containing sequence

In conclusion, the observations reported here demonstrate that a short, tyrosine-containing sequence within the cytoplasmic tail of TGN38 is sufficient to confer TGN-localization to a reporter protein, Tac, and reveal a novel function for a cytoplasmic tyrosine-based motif-the ability to mediate protein localization to the TGN. Study of other proteins, such as furin, will ascertain whether similar cytoplasmic signals mediate localization of additional type I integral membrane proteins to the Golgi complex. The conservation of TGN localization across species boundaries and the demonstrated importance of the cytoplasmic domain for localization of yeast proteins to the late Golgi suggest the existence of an evolutionarily conserved mechanism that relies on the specific recognition of cytoplasmic determinants. The identification of sequences that are sufficient for TGN localization should allow the development of biochemical and genetic approaches to define the mechanisms by which membrane proteins become localized to the TGN.