Estrogen Modulation of Prolactin Gene Expression Requires an Intact Mitogen-Activated Protein Kinase Signal Transduction Pathway in Cultured Rat Pituitary Cells
| Autor: | Yong-Nyun Kim, Jyoti J. Watters, Tae-Yon Chun, Paul J. Bertics, Jack Gorski |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
MAPK/ERK pathway
Transcription Genetic MAP Kinase Kinase 1 Estrogen receptor Endocrinology Benzoquinones Cyclin D1 Enzyme Inhibitors Phosphorylation Cells Cultured Mitogen-Activated Protein Kinase 1 Mitogen-Activated Protein Kinase 3 Quinones General Medicine src-Family Kinases Pituitary Gland Female Steroids Mitogen-Activated Protein Kinases Signal transduction hormones hormone substitutes and hormone antagonists Signal Transduction endocrine system MAP Kinase Signaling System Lactams Macrocyclic Protein Serine-Threonine Kinases Biology Prolactin cell Nitriles Butadienes Animals RNA Messenger c-Raf Protein kinase A Molecular Biology Flavonoids Mitogen-Activated Protein Kinase Kinases Dose-Response Relationship Drug Cyclin-dependent kinase 4 Cyclin-dependent kinase 2 Estrogens Molecular biology Rats Inbred F344 Prolactin Rats Enzyme Activation Proto-Oncogene Proteins c-raf Pyrimidines Gene Expression Regulation Rifabutin biology.protein Pyrazoles Tyrosine |
| Zdroj: | Molecular Endocrinology. 14:1872-1881 |
| ISSN: | 1944-9917 0888-8809 |
| Popis: | Expression of the PRL gene is regulated by many factors, including cAMP, estradiol (E2), phorbol esters, epidermal growth factor (EGF), and TRH. The promoter region of the rat PRL gene has been shown to contain DNA sequences that are thought to support the direct interaction of estrogen receptors (ERs) with DNA. It is by this direct ER/DNA interaction that estrogen is thought to modulate expression of PRL. We report here that estrogeninduced PRL expression requires an intact mitogen-activated protein kinase (MAPK) signal transduction pathway in cultured rat pituitary cells (PR1 lactotroph and GH3 somatolactotroph cell lines). Interfering with the MAPK signaling cascade by inhibiting the activity of MAPK kinase (MEK) ablates the ability of estrogen to induce PRL mRNA and protein. In these cell lines, estrogen activates extracellular regulated protein kinases ERK-1 and ERK-2 enzyme activities maximally within 10 min of 1 nM E2 treatment. This activity is blocked by pretreatment of the cells with the MEK inhibitors PD98059 and UO126. The mechanism by which ERKs-1 and -2 are activated by estrogen appears to be independent of c-Src since the effects of estrogen on PRL gene expression are not affected by herbimycin A or PP1 administration. c-Raf-1 may be involved in the effects of E2 because estrogen causes the rapid and transient tyrosine phosphorylation of c-Raf-1. The ER antagonist ICI 182,780 blocks both ERK-1 and ERK-2 activation in addition to PRL protein and mRNA, implying a central role for the classical ER in the activation of the MAPK pathway resulting in PRL gene expression. |
| Databáze: | OpenAIRE |
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