Subcellular distribution and targeting of the intracellular chloride channel p64

p64 is an intracellular chloride channel originally identified in bovine kidney microsomes. Using a combination of immunofluorescent and electron microscopic technique, we demonstrate that p64 resides in the limiting membranes of perinuclear dense core vesicles which appear to be regulated secretory vesicles. Heterologous expression of p64 in PancI cells, a cell type which does not normally express p64, results in targeting 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 and the N-terminal domain is necessary to deliver p64 to the appropriate membrane compartment.