钙／钙调蛋白依赖性丝氨酸蛋白激酶在胰岛素囊泡分泌过程中的作用

Role of Calcium/calmodulin-dependent serine protein kinase in insulin granules secretion

目的探讨钙／钙调蛋白依赖性丝氨酸蛋白激酶（CASK）在胰岛素囊泡分泌过程中的作用。方法体外培养胰岛B细胞株INS-1细胞，干扰或过表达CASK同时结合腺甘酸环化酶激动剂forskolin或硝苯地平处理，使用电镜观察干扰CASK后胰岛素囊泡的锚定情况和数量。两组问比较采用t检验，多组间比较采用方差分析。结果（1）干扰CASK后，forskolin促胰岛素分泌的效应减弱[（4．5±0．4）%比（2．7±0．6）％，t=6．019，P〈0．01]。（2）过表达CASK不能逆转硝苯地平处理后引起的胰岛素分泌下降[（1．4±0．1）％比（1．5±0．3）％，t=0．40，P〉0．05]。（3）干扰CASK后胰岛素囊泡在细胞膜上的锚定明显减少，而总胰岛素囊泡数量组间差异无统计学意义[（140±30）比（123±45）个，t=0．44，P〉0．05]。结论CASK参与forskolin促胰岛素分泌的过程，其作用环节可能位于钙离子通道的下游；CASK很可能参与了胰岛素囊泡分泌的锚定过程。

Objective To investigate the role of Calcium/calmodulin-dependent serine protein kinase （CASK） in insulin granules secretion. Methods Interference or overexpression of CASK in combination with forskolin or nifidipine treatment were applied to explore the role of CASK in insulin granules secretion in pancreatic G-cell line （INS-1 cells）. The anchoring and number of insulin granules were detected using electro microscope after CASK interference in primary islets. The t test was used for pairwise comparison, and differences among groups were compared by analysis of variance. Results （ 1 ） Knockdown of CASK suppressed the effect of forskolin mediated insulin secretion [（4.5 ±0.4）% vs （2.7 ± 0.6）%, t=6.019, P〈0.01]. （2） The decrease of insulin secretion with nifidipine treatment was not reversed by overexpression of CASK [（1.4 ± 0.1）% vs （1.5 ± 0.3）%, t=0.40, P〉0.05]. （3）The anchoring of insulin granules to cell member was dramatically attenuated after CASK interference, while the total number of insulin granules was not statistically different between groups [（140±30） vs （123 ±45）, t=0.44, P〉0.05]. Conclusion CASK is involved in foskoline induced insulin secretion. CASK may play a role in the downstream of calcium channel. CASK is probably involved in the anchoring of insulin granules.