p70(s6k) is activated by CCK in rat pancreatic acini
p70(s6k) is activated by CCK in rat pancreatic acini
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DOI：
10.1152/ajpcell.1997.273.1.c101
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发表时间：
1997-07-01
影响因子：
5.5
通讯作者：
Williams, JA
中科院分区：
文献类型：
--
作者：
Bragado, MJ;Groblewski, GE;Williams, JA
免疫印迹法、免疫沉淀法和激酶法检测大鼠胰腺腺泡内p70(S6K)-P85(S6K)的表达和活性。CCK对p70(S6K)活性的刺激是双相的，早期最大值在5min，晚期最大值在60min。CCK促进p70(S6K)活性的阈值浓度为下午3，1 nM时作用最强。卡巴胆碱和蛙皮素也能激活p70(S6K)，但不能激活血管活性肠肽。蛋白激酶C(PKC)激动剂(12-O-十四酰佛波醇13-乙酸酯)、钙离子载体(离子霉素)和3‘，5’-环磷酸腺苷的衍生物仅引起p70(S6K)活性的轻微增加。雷帕霉素有效地阻断了基础和CCK刺激的p70(S6K)活性，这种抑制作用可被过量的FK-506逆转。磷脂酰肌醇3-激酶抑制剂wortmannin能有效抑制CCK激活的p70(S6K)，而酪氨酸激酶抑制剂genistein仅有部分作用。在抑制p70(S6K)活性的浓度下，雷帕霉素和ae wortmannin都不能抑制淀粉酶的释放。因此，CCK激活p70(S6K)的途径不是由蛋白激酶C或细胞内钙动员介导的，而可能是由磷脂酰肌醇S激酶介导的。雷帕霉素抑制p70(S6K)活性的作用是通过与12 kDa的免疫叶绿素FK-506结合蛋白介导的。P70(S6K)不参与CCK诱导的消化酶分泌。
The expression and activity of p70(s6k)-p85(s6k) in isolated rat pancreatic acini were revealed by Western blotting, immunoprecipitation, and kinase assay. Cholecystokinin (CCK) stimulation of p70(s6k) activity was biphasic, with an early phase maximum at 5 min and a late phase maximum at 60 min. The threshold concentration of CCK to increase p70(s6k) activity was 3 pM, and the maximal effect was seen at 1 nM CCK. Carbachol and bombesin, but not vasoactive intestinal peptide, also activated p70(s6k). The protein kinase C (PKC) activator (12-O-tetradecanoylphorbol 13-acetate), the calcium ionophore (ionomycin), and a derivative of adenosine 3',5'-cyclic monophosphate induced only a slight increase in p70(s6k) activity. Rapamycin potently blocked both the basal and the CCK-stimulated p70(s6K) activity, and this inhibition was reversed by an excess of FK-506. The phosphatidylinositol 3-kinase inhibitor, wortmannin, potently inhibited p70(s6k) activation by CCK, whereas the tyrosine kinase inhibitor genistein had only a partial effect. Neither rapamycin nor ae wortmannin inhibited amylase release at concentrations that inhibited p70(s6k) activity. Thus the activation pathway of p70(s6k) by CCK is not mediated by PKC or mobilization of intracellular calcium but seems to be mediated by phosphatidylinositol S-kinase. The effect of rapamycin to inhibit p70(s6k) activity is mediated by binding to the immunophyllin FK-506-binding protein of 12 kDa. The p70(s6k) is not involved in the secretion of digestive enzymes induced by CCK.