SUBCELLULAR-DISTRIBUTION AND TARGETING OF THE INTRACELLULAR CHLORIDE CHANNEL P64

p64 is an intracellular chloride channel originally identified in bovi ne kidney microsomes. Using a combination of immunofluorescent and ele ctron microscopic techniques, we demonstrate that p64 resides in the l imiting membranes of perinuclear dense core vesicles which appear to b e regulated secretory vesicles. Heterologous expression of p64 in Panc I cells, a cell type which does not normally express p64, results in t argeting to a similar compartment. Mutagenesis experiments demonstrate that both the N- and C-terminal domains of the protein independently contribute to subcellular distribution of the protein. The C-terminal domain functions to prevent expression of p64 on the plasma membrane a nd the N-terminal domain is necessary to deliver p64 to the appropriat e membrane compartment.