Hormonal regulation of MAP kinase in cultured rat inner medullary collecting tubule cells.
Hormonal regulation of MAP kinase in cultured rat inner medullary collecting tubule cells.
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培养的大鼠内髓集合管细胞中 MAP 激酶的激素调节。
DOI：
10.1152/ajprenal.1994.267.3.f366
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Berl,T
中科院分区：
文献类型：
--
作者：
Heasley,LE;Senkfor,SI;Winitz,S;Strasheim,A;Teitelbaum,I;Berl,T
丝裂原活化蛋白（MAP）激酶是一种广泛表达的蛋白丝氨酸/苏氨酸激酶，其充当许多信号传导途径的汇聚点，包括受体酪氨酸激酶、G蛋白偶联受体和蛋白激酶C（PKC）。在体外培养的大鼠内髓集合管（RIMCT）细胞上研究了MAP激酶的激素调节。加压素和β-肾上腺素能激动剂都不能刺激MAP激酶，尽管能明显刺激环磷酸腺苷（cAMP）依赖性蛋白激酶。相反，卡巴胆碱，ATP和表皮生长因子（EGF），这是已知的拮抗加压素的作用，在RIMCT，刺激MAP激酶通路。这种刺激被直接激活PKC的佛波酯12-O-十四酰基佛波醇-13-乙酸酯模拟。EGF和卡巴胆碱激活MAP激酶的效力与它们抑制加压素刺激的cAMP积累的效力相似。为了评估Gi蛋白在这些刺激事件中的作用，用百日咳毒素预处理RIMCT细胞以抑制Gi介导的信号传导。百日咳毒素不影响ATP或EGF刺激的MAP激酶，但完全抑制卡巴胆碱刺激，表明Gi蛋白介导毒蕈碱刺激。RIMCT细胞长时间暴露于高浓度佛波醇酯下调PKC消融卡巴胆碱和ATP刺激的MAP激酶，但不是EGF刺激的MAP激酶，表明PKC是参与MAP激酶激活嘌呤和毒蕈碱激动剂的网络的一个组成部分。激素刺激的侧性的调查表明，EGF刺激的MAP激酶是高度极化的，只发生在基底外侧表面，而卡巴胆碱刺激MAP激酶类似于从细胞表面。（250字处删节）
Mitogen-activated protein (MAP) kinase is a widely expressed protein serine/threonine kinase that serves as a convergence point for many signaling pathways including receptor tyrosine kinases, G protein-coupled receptors, and protein kinase C (PKC). The hormonal regulation of MAP kinase was studied in cultured established rat inner medullary collecting tubule (RIMCT) cells. Neither vasopressin nor beta-adrenergic agonists stimulated MAP kinase, despite clear stimulation of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase. In contrast, carbachol, ATP, and epidermal growth factor (EGF), which are known to antagonize vasopressin action in the RIMCT, stimulated the MAP kinase pathway. This stimulation was mimicked by the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate, which directly activates PKC. The potency with which EGF and carbachol activated MAP kinase was similar to the potency with which they inhibited vasopressin-stimulated cAMP accumulation. To assess the role of Gi proteins in these stimulatory events, RIMCT cells were pretreated with pertussis toxin to inhibit Gi-mediated signaling. Pertussis toxin did not influence ATP- or EGF-stimulated MAP kinase, but completely inhibited carbachol stimulation, suggesting that Gi proteins mediate muscarinic stimulation. Prolonged exposure of RIMCT cells to high phorbol ester concentrations to downregulate PKC ablated carbachol- and ATP-stimulated MAP kinase, but not EGF-stimulated MAP kinase, suggesting that PKC is a component of the network involved in MAP kinase activation by purinergic and muscarinic agonists. Investigation of the sidedness of the hormonal stimulations indicated that EGF-stimulated MAP kinase was highly polarized, occurring exclusively from the basolateral surface, whereas carbachol stimulated MAP kinase similarly from either cell surfaces.(ABSTRACT TRUNCATED AT 250 WORDS)