Protein kinase C-beta-mediated complex formation between tyrosinase and TRP-1.
Tyrosinase, the key enzyme in melanogenesis, is activated when protein kinase C-beta (PKC-beta) phosphorylates the serine residues at amino acid positions 505 and 509. To further elucidate the mechanism by which phosphorylation of tyrosinase by PKC-beta leads to the activation of tyrosinase, a possible complex formation between phosphorylated tyrosinase and tyrosinase related protein-1 (TRP-1), a melanogenic protein suggested to influence tyrosinase activity, was investigated. Non-denaturing gel electrophoresis of melanocyte lysate revealed two molecular weight forms of TRP-1 and a monoclonal antibody against TRP-1 co-immunoprecipitated tyrosinase and TRP-1, suggesting that TRP-1 may be complexed with tyrosinase. Activation of PKC by treating melanocytes with phorbol 12,13-dibutyrate (PDBu) increased the level of tyrosinase co-immunoprecipitated with TRP-1; whereas a selective PKC inhibitor bisindolylmaleimide inhibited PDBu-induced increase in the level of tyrosinase co-immunoprecipitated with TRP-1. These results suggest that phosphorylation of tyrosinase by PKC-beta induces a complex formation between tyrosinase and TRP-1.
Wu
Heng
H
Department of Hematology/Oncology, Massachusetts General Hospital, Boston, MA 02114, USA.
Park
Hee-Young
HY
D002478:Cells, Cultured; D004789:Enzyme Activation; D006801:Humans; D007231:Infant, Newborn; D046911:Macromolecular Substances; D008544:Melanocytes / Q000201:enzymology*; D008562:Membrane Glycoproteins; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D010088:Oxidoreductases; D010766:Phosphorylation; D011485:Protein Binding; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D011506:Proteins / Q000378:metabolism*
D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D009097:Multienzyme Complexes; D011506:Proteins; D010088:Oxidoreductases; C489799:TYRP1 protein, human; C064056:tyrosinase-related protein-1; D014442:Monophenol Monooxygenase; D011493:Protein Kinase C; D064546:Protein Kinase C beta