Epitope mapping of two isoforms of a trans Golgi network specific integral membrane protein TGN38/41

TGN38/41 is an integral membrane protein predominantly located in the trans Golgi network (TGN) of rat (NRK) cells. We have used a cDNA expression system to map the epitopes recognised by a panel of antibodies raised to TGN38/41 as a preliminary step in the accurate identification of the region(s) of the molecule responsible for its correct intracellular location. These studies have confirmed the predicted topology of the molecule, and have identified a region in the cytoplasmic domain which is immunologically (and hence potentially functionally) conserved between species.