PI3K regulates endocytosis after insulin secretion by mediating signaling crosstalk between Arf6 and Rab27a
PI3K regulates endocytosis after insulin secretion by mediating signaling crosstalk between Arf6 and Rab27a
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DOI：
10.1242/jcs.180141
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发表时间：
2016-02
影响因子：
4
通讯作者：
Mami Yamaoka;T. Ando;T. Terabayashi;Mitsuhiro Okamoto;M. Takei;Tomoki Nishioka;K. Kaibuchi;K. Matsunaga;Ray Ishizaki;T. Izumi;I. Niki;T. Ishizaki;Toshihide Kimura
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作者：
Mami Yamaoka;T. Ando;T. Terabayashi;Mitsuhiro Okamoto;M. Takei;Tomoki Nishioka;K. Kaibuchi;K. Matsunaga;Ray Ishizaki;T. Izumi;I. Niki;T. Ishizaki;Toshihide Kimura
摘要在分泌细胞中，胞吞作用与胞吐作用相结合，使分泌得以正常进行。虽然内吞作用对于维持分泌前后的细胞内稳态是至关重要的，但关于促分泌素诱导的分泌细胞内吞作用的知识仍然有限。在这里，我们搜索了与Rab 27 a GTP酶激活蛋白（GAP）EPI 64（也称为TBC 1D 10A）相互作用的蛋白质，并在胰腺β细胞中鉴定了Arf 6鸟嘌呤核苷酸交换因子（GEF）ARNO（也称为CYTH 2）。我们发现胰岛素促分泌素葡萄糖通过磷酸肌醇3-激酶（PI 3 K）促进磷脂酰肌醇（3，4，5）-三磷酸（PIP 3）的产生，从而将ARNO募集到质膜的细胞内侧。外周ARNO通过其对Arf 6的GEF活性促进网格蛋白组装并调节内吞作用的早期阶段。我们还发现，外周ARNO将EPI 64募集到相同区域，并且这种相互作用需要胰腺β细胞中葡萄糖诱导的内吞作用。鉴于GTP和GDP结合的Rab 27 a调节胞吐和内吞的后期阶段，我们的研究结果表明葡萄糖诱导的PI 3 K激活在外吞-内吞偶联中起关键作用，并且ARNO和EPI 64在不同阶段调节内吞。总结：胰岛素促分泌素葡萄糖通过促进Arf 6和Rab 27 a通路之间的信号串扰激活PI 3 K并诱导内吞作用。
ABSTRACT In secretory cells, endocytosis is coupled to exocytosis to enable proper secretion. Although endocytosis is crucial to maintain cellular homeostasis before and after secretion, knowledge about secretagogue-induced endocytosis in secretory cells is still limited. Here, we searched for proteins that interacted with the Rab27a GTPase-activating protein (GAP) EPI64 (also known as TBC1D10A) and identified the Arf6 guanine-nucleotide-exchange factor (GEF) ARNO (also known as CYTH2) in pancreatic β-cells. We found that the insulin secretagogue glucose promotes phosphatidylinositol (3,4,5)-trisphosphate (PIP3) generation through phosphoinositide 3-kinase (PI3K), thereby recruiting ARNO to the intracellular side of the plasma membrane. Peripheral ARNO promotes clathrin assembly through its GEF activity for Arf6 and regulates the early stage of endocytosis. We also found that peripheral ARNO recruits EPI64 to the same area and that the interaction requires glucose-induced endocytosis in pancreatic β-cells. Given that GTP- and GDP-bound Rab27a regulate exocytosis and the late stage of endocytosis, our results indicate that the glucose-induced activation of PI3K plays a pivotal role in exocytosis–endocytosis coupling, and that ARNO and EPI64 regulate endocytosis at distinct stages. Summary: The insulin secretagogue glucose activates PI3K and induces endocytosis through promoting signaling crosstalk between Arf6 and Rab27a pathways.