1,10-Phenanthroline phosphorylates (activates) MAP kinase in Xenopus oocytes.
The membrane-permeable intracellular heavy metal chelator, 1,10-phenanthroline, which prevents progesterone-induced germinal vesicle breakdown (GVBD), would be expected to regulate phosphorylation (activation) of the MAP kinase (MAPK) cascade in Xenopus oocytes. Here, our experiments show that 1,10-phenanthroline itself results in the phosphorylation of MAPK in both oocytes and a cell-free system. In contrast, 1,7-phenanthroline, the nonchelating analogue, had no effect. A supplement of zinc (as a heavy metal) given to 1,10-phenanthroline-loaded oocytes suppressed the stimulatory effects of 1,10-phenanthroline, while 1,10-phenanthroline withdrawal caused dephosphorylation of activated MAPK. Further, treatment with a MEK (a MAPK kinase) inhibitor, PD 098059 or U0126, suppressed 1,10-phenanthroline-stimulated MAPK phosphorylation, indicating that 1,10-phenanthroline can phosphorylate MAPK in a MEK-dependent fashion. Our results suggest that phosphorylation of MAPK by 1,10-phenanthroline depends on the interaction of MEK. Thus, the intracellular heavy metal (zinc) regulates MAPK phosphorylation and 1,10-phenanthroline can serve as a unique tool for investigating MAPK phosphorylation mechanism.
Watanabe
Ken-Ichi
K
Department of Biology and Geosciences, Faculty of Science, Shizuoka University, Ohya 836, Shizuoka 422-8529, Japan. kwatanabe@nirs.go.jp
Tokumoto
Toshinobu
T
Ishikawa
Katsutoshi
K
D000818:Animals; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D002474:Cell-Free System / Q000187:drug effects / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007700:Kinetics; D008301:Maleimides / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D004369:Pentetic Acid / Q000494:pharmacology; D010618:Phenanthrolines / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D011374:Progesterone / Q000494:pharmacology; D013912:Threonine / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D014982:Xenopus laevis; D019287:Zinc Sulfate / Q000494:pharmacology
D002070:Butadienes; D002867:Chromones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007211:Indoles; D008301:Maleimides; D009025:Morpholines; D009570:Nitriles; D010618:Phenanthrolines; C113580:U 0126; D005576:Colforsin; C053486:1,7-phenanthroline; D013912:Threonine; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D014443:Tyrosine; D011374:Progesterone; D019287:Zinc Sulfate; D004369:Pentetic Acid; D003513:Cycloheximide; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; C088060:bisindolylmaleimide; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; C025205:1,10-phenanthroline