The control of insulin release from pancreatic beta cells helps ensure proper blood glucose level, which is critical for human health. Protein kinase C has been shown to be one key control mechanism for this process. After glucose stimulation, calcium influx into beta cells triggers exocytosis of insulin-containing dense-core granules and activates protein kinase C via calcium-dependent phospholipase C-mediated generation of diacylglycerol. Activated protein kinase C potentiates insulin release by enhancing the calcium sensitivity of exocytosis, likely by affecting two main pathways that could be linked: (1) the reorganization of the cortical actin network, and (2) the direct phosphorylation of critical exocytotic proteins such as munc18, SNAP25, and synaptotagmin. Here, we review what is currently known about the molecular mechanisms of protein kinase C action on each of these pathways and how these effects relate to the control of insulin release by exocytosis. We identify remaining challenges in the field and suggest how these challenges might be addressed to advance our understanding of the regulation of insulin release in health and disease.

中文翻译：

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β细胞中钙依赖性蛋白激酶C对胰岛素胞吐的调节。

控制胰腺β细胞释放胰岛素有助于确保适当的血糖水平，这对人体健康至关重要。已经证明蛋白激酶C是该过程的一种关键控制机制。葡萄糖刺激后，钙流入β细胞会触发含胰岛素的致密颗粒的胞吐作用，并通过钙依赖性磷脂酶C介导的二酰基甘油的生成来激活蛋白激酶C。活化的蛋白激酶C通过增强胞吐作用的钙敏感性来增强胰岛素的释放，这可能是通过影响可能相关的两个主要途径进行的：（1）皮质肌动蛋白网络的重组，以及（2）关键胞吐蛋白的直接磷酸化，例如munc18，SNAP25和突触结合素。这里，我们回顾了目前有关蛋白激酶C在这些途径中的每一种作用的分子机制以及这些作用与胞吐作用对胰岛素释放的控制之间的关系的已知知识。我们确定了该领域中尚存的挑战，并建议如何应对这些挑战，以增进我们对健康和疾病中胰岛素释放调节的理解。