Activation of mitogen-activated protein kinases by gonadotropins and cyclic adenosine 5'-monophosphates in porcine granulosa cells
Activation of mitogen-activated protein kinases by gonadotropins and cyclic adenosine 5'-monophosphates in porcine granulosa cells
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DOI：
10.1095/biolreprod55.1.111
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发表时间：
1996-07-01
影响因子：
3.6
通讯作者：
Wimalasena, J
中科院分区：
文献类型：
--
作者：
Cameron, MR;Foster, JS;Wimalasena, J
已知多种生长因子和鸟苷三磷酸（CTP）结合蛋白连接受体可激活丝裂原活化蛋白激酶（MAPK）；然而，没有证据表明糖蛋白激素可以激活MAPK通路。利用猪颗粒细胞（PGC），我们发现生理浓度的LH和FSH增加细胞质中p44（MAPK）细胞外调节激酶1 （ERK1）的酶活性，但不增加p42（MAPK) （ERK2）的酶活性，2）细胞核中ERK1和ERK2的酶活性。LH比FSH更快地激活胞质ERK1。环AMP增加了细胞质和细胞核中ERK1和ERK2的激酶活性。促性腺激素和cAMP对ERK1的激活伴随着激酶酪氨酸磷酸化的增加。免疫组织化学研究表明，未经处理的PCC培养物中MAPK主要是细胞质染色，而促性腺激素治疗导致核免疫反应性增加，表明MAPK易位到核。细胞核ERK1和ERK2的易位和增加被延迟，并与胞质ERK1活性的降低相一致。表皮生长因子（EGF）可使PGC细胞质中ERK1和erk2相关激酶活性提高7-8倍，而LH、FSH或cAMP可使细胞质ERK1激酶活性提高3-4倍。总之，我们首次证明了促性腺激素（和cAMP）可以在适当的靶细胞中激活MAPK。
A variety of growth factors and guanosine triphosphate (CTP) binding protein-linked receptors are known to activate mitogen activated protein kinases (MAPK); however, no evidence exists demonstrating activation of the MAPK pathway by glycoprotein hormones. Using porcine granulosa cells (PGC), we show that physiological concentrations of LH and FSH increase enzymatic activity 1) of p44(MAPK) extracellular regulated kinase 1 (ERK1) but not that of p42(MAPK) (ERK2) in the cytosol and 2) of both ERK1 and ERK2 in the nucleus. Cytosolic ERK1 was activated by LH more rapidly than by FSH. Cyclic AMP increased kinase activities of both ERK1 and ERK2 in the cytoplasm as well as in the nucleus. Activation of ERK1 by gonadotropins and cAMP was accompanied by increased tyrosine phosphorylation of the kinase. Immunohistochemical studies demonstrated predominantly cytoplasmic staining for MAPK in untreated PCC cultures whereas treatment with gonadotropins led to increased nuclear immunoreactivity indicating translocation of MAPK to the nucleus. The translocation as well as increase in nuclear ERK1 and ERK2 was delayed and coincided with a decrease in cytosolic ERK1 activity. Epidermal growth factor (EGF) increased ERK1 and ERK2-associated kinase activity 7-8-fold in the cytoplasm of PGC, while kinase activity of cytoplasmic ERK1 was enhanced 3-4-fold by LH, FSH, or cAMP. In summary, we have for the first time demonstrated that gonadotropins (and cAMP) can activate MAPK in appropriate target cells.