A Rab10-ACAP1-Arf6 GTPases cascade modulates M4 muscarinic acetylcholine receptor trafficking and signaling
A Rab10-ACAP1-Arf6 GTPases cascade modulates M4 muscarinic acetylcholine receptor trafficking and signaling
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Rab10-ACAP1-Arf6 GTPases 级联调节 M4 毒蕈碱乙酰胆碱受体运输和信号传导
DOI：
10.1007/s00018-023-04722-x
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发表时间：
2023-04-01
影响因子：
8
通讯作者：
Zhang，Rongying
中科院分区：
文献类型：
--
作者：
Xu，Rongmei;Wan，Min;Zhang，Rongying
膜运输过程调节G蛋白偶联受体的活性。毒蕈碱乙酰胆碱受体（machr）是神经系统疾病的高度追求的药物靶点，但控制这些受体运输的细胞机制在很大程度上仍然难以捉摸。在这里，我们揭示了小GTPase Rab10作为M4 mAChR激活后转运的负调节因子的作用及其潜在机制。我们发现，组成型活性Rab10在rab5阳性的早期内体中阻止受体，并显著阻碍m4介导的Ca2+信号的再敏化。从机制上讲，M4与Rab10-GTP结合，这需要在第三个细胞内环内的基序386rkkrqmaa393 （R386-A393）。此外，Rab10-GTP通过募集Arf6 gtpase激活蛋白ACAP1使Arf6失活。引人注目的是，r386 - a393基序的缺失导致M4绕过Rab10的控制，切换到rab4促进的快速循环途径，从而重复使用受体。因此，Rab10通过gtp绑定状态和gdp绑定状态之间的循环，耦合了货物分拣和膜运输调节。我们的研究结果表明Rab10像分子制动器一样与M4结合并控制受体通过核内体的运输，从而调节信号传导，并且这种调节在mAChR亚型中是特异性的。
Membrane trafficking processes regulate the G protein-coupled receptor activity. The muscarinic acetylcholine receptors (mAChRs) are highly pursued drug targets for neurological diseases, but the cellular machineries that control the trafficking of these receptors remain largely elusive. Here, we revealed the role of the small GTPase Rab10 as a negative regulator for the post-activation trafficking of M4 mAChR and the underlying mechanism. We show that constitutively active Rab10 arrests the receptor within Rab5-positive early endosomes and significantly hinders the resensitization of M4-mediated Ca2+signaling. Mechanistically, M4 binds to Rab10-GTP, which requires the motif386RKKRQMAA393(R386-A393) within the third intracellular loop. Moreover, Rab10-GTP inactivates Arf6 by recruiting the Arf6 GTPase-activating protein, ACAP1. Strikingly, deletion of the motif R386-A393causes M4 to bypass the control by Rab10 and switch to the Rab4-facilitated fast recycling pathway, thus reusing the receptor. Therefore, Rab10 couples the cargo sorting and membrane trafficking regulation through cycle between GTP-bound and GDP-bound state. Our findings suggest a model that Rab10 binds to the M4 like a molecular brake and controls the receptor’s transport through endosomes, thus modulating the signaling, and this regulation is specific among the mAChR subtypes.