Pink-eyed dilution protein modulates arsenic sensitivity and intracellular glutathione metabolism.
Mutations in the mouse p (pink-eyed dilution) and human P genes lead to melanosomal defects and ocular developmental abnormalities. Despite the critical role played by the p gene product in controlling tyrosinase processing and melanosome biogenesis, its precise biological function is still not defined. We have expressed p heterologously in the yeast Saccharomyces cerevisiae to study its function in greater detail. Immunofluorescence studies revealed that p reaches the yeast vacuolar membrane via the prevacuolar compartment. Yeast cells expressing p exhibited increased sensitivity to a number of toxic compounds, including arsenicals. Similarly, cultured murine melanocytes expressing a functional p gene were also found to be more sensitive to arsenical compounds compared with p-null cell lines. Intracellular glutathione, known to play a role in detoxification of arsenicals, was diminished by 50% in p-expressing yeast. By using the glutathione-conjugating dye monochlorobimane, in combination with acivicin, an inhibitor of vacuolar gamma-glutamyl cysteine transpeptidase, involved in the breakdown of glutathione, we found that p facilitates the vacuolar accumulation of glutathione. Our data demonstrate that the pink-eyed dilution protein increases cellular sensitivity to arsenicals and other metalloids and can modulate intracellular glutathione metabolism.
Staleva
Liliana
L
The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York 10016, USA.
Manga
Prashiela
P
Orlow
Seth J
SJ
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001151:Arsenic / Q000378:metabolism*; D001692:Biological Transport; D002352:Carrier Proteins; D002499:Centrifugation, Density Gradient; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D005822:Genetic Vectors; D005838:Genotype; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D020128:Inhibitory Concentration 50; D008544:Melanocytes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D026901:Membrane Transport Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D009154:Mutation; D016366:Open Reading Frames; D010957:Plasmids / Q000378:metabolism; D011796:Quinacrine / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013347:Subcellular Fractions; D013395:Sucrose / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013997:Time Factors
D002352:Carrier Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C489600:OCA2 protein, human; D013438:Sulfhydryl Compounds; C076239:P protein, mouse; D013395:Sucrose; D000135:Acid Phosphatase; D005978:Glutathione; D011796:Quinacrine; D001151:Arsenic