Estrogen-induced activation of the mitogen-activated protein kinase cascade in the cerebral cortex of estrogen receptor-alpha knock-out mice.
We have shown previously in the developing cerebral cortex that estrogen elicits the rapid and sustained activation of multiple signaling proteins within the mitogen-activated protein (MAP) kinase cascade, including B-Raf and extracellular signal-regulated kinase (ERK). Using estrogen receptor (ER)-alpha gene-disrupted (ERKO) mice, we addressed the role of ER-alpha in mediating this action of estrogen in the brain. 17beta-Estradiol increased B-Raf activity and MEK (MAP kinase/ERK kinase)-dependent ERK phosphorylation in cerebral cortical explants derived from both ERKO and their wild-type littermates. The ERK response was stronger in ERKO-derived cultures but, unlike that of wild-type cultures, was not blocked by the estrogen receptor antagonist ICI 182,780. Surprisingly, both the ER-alpha selective ligand 16alpha-iodo-17beta-estradiol and the ER-beta selective ligand genistein failed to elicit ERK phosphorylation, suggesting that a different mechanism or receptor may mediate estrogen-induced ERK phosphorylation in the cerebral cortex. Interestingly, the transcriptionally inactive stereoisomer 17alpha-estradiol did elicit a strong induction of ERK phosphorylation, which, together with the inability of the ER-alpha- and ER-beta-selective ligands to elicit ERK phosphorylation, and of ICI 182,780 to block the actions of estradiol in ERKO cultures, supports the hypothesis that a novel, estradiol-sensitive and ICI-insensitive estrogen receptor may mediate 17beta-estradiol-induced activation of ERK in the brain.
Singh
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Department of Anatomy, Center for Neurobiology and Behavior and Reproductive Sciences, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
Sétáló
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Guan
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Frail
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Toran-Allerand
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D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000737:chemistry / Q000166:cytology / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D029968:Escherichia coli Proteins; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D047628:Estrogen Receptor alpha; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D000077267:Fulvestrant; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D005838:Genotype; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000502:physiology; D008297:Male; D026901:Membrane Transport Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D011960:Receptors, Estrogen / Q000235:genetics*
D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D004965:Estrogen Antagonists; D047628:Estrogen Receptor alpha; D005419:Flavonoids; D026901:Membrane Transport Proteins; D011960:Receptors, Estrogen; C062064:raffinose permease, E coli; D000077267:Fulvestrant; D004958:Estradiol; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one