Gurda Grzegorz T, Guo LiLi, Lee Sae-Hong, Molkentin Jeffery D, Williams John A
Department of Molecular and Integrative Physiology, The University of Michigan Medical School, Ann Arbor, MI 48109-0622, USA.
Mol Biol Cell. 2008 Jan;19(1):198-206. doi: 10.1091/mbc.e07-05-0430. Epub 2007 Oct 31.
Elevated endogenous cholecystokinin (CCK) release induced by protease inhibitors leads to pancreatic growth. This response has been shown to be mediated by the phosphatase calcineurin, but its downstream effectors are unknown. Here we examined activation of calcineurin-regulated nuclear factor of activated T-cells (NFATs) in isolated acinar cells, as well as in an in vivo model of pancreatic growth. Western blotting of endogenous NFATs and confocal imaging of NFATc1-GFP in pancreatic acini showed that CCK dose-dependently stimulated NFAT translocation from the cytoplasm to the nucleus within 0.5-1 h. This shift in localization correlated with CCK-induced activation of NFAT-driven luciferase reporter and was similar to that induced by a calcium ionophore and constitutively active calcineurin. The effect of CCK was dependent on calcineurin, as these changes were blocked by immunosuppressants FK506 and CsA and by overexpression of the endogenous protein inhibitor CAIN. Parallel NFAT activation took place in vivo. Pancreatic growth was accompanied by an increase in nuclear NFATs and subsequent elevation in expression of NFAT-luciferase in the pancreas, but not in organs unresponsive to CCK. The changes also required calcineurin, as they were blocked by FK506. We conclude that CCK activates NFATs in a calcineurin-dependent manner, both in vitro and in vivo.
蛋白酶抑制剂诱导内源性胆囊收缩素（CCK）释放增加会导致胰腺生长。这种反应已被证明是由磷酸酶钙调神经磷酸酶介导的，但其下游效应器尚不清楚。在这里，我们研究了在分离的腺泡细胞以及胰腺生长的体内模型中钙调神经磷酸酶调节的活化T细胞核因子（NFATs）的激活情况。对胰腺腺泡中内源性NFATs进行蛋白质免疫印迹分析以及对NFATc1-GFP进行共聚焦成像显示，CCK在0.5-1小时内剂量依赖性地刺激NFAT从细胞质转运至细胞核。这种定位变化与CCK诱导的NFAT驱动的荧光素酶报告基因的激活相关，并且类似于钙离子载体和组成型活性钙调神经磷酸酶所诱导的变化。CCK的作用依赖于钙调神经磷酸酶，因为这些变化被免疫抑制剂FK506和环孢素A以及内源性蛋白抑制剂CAIN的过表达所阻断。体内也发生了平行的NFAT激活。胰腺生长伴随着胰腺中核NFATs的增加以及随后NFAT-荧光素酶表达的升高，但在对CCK无反应的器官中则没有这种情况。这些变化也需要钙调神经磷酸酶，因为它们被FK506所阻断。我们得出结论，CCK在体外和体内均以钙调神经磷酸酶依赖性方式激活NFATs。
