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PTP-MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates
bioRxiv - Cell Biology Pub Date : 2020-09-17 , DOI: 10.1101/822031
Yun-Fei Xu , Xu Chen , Zhao Yang , Peng Xiao , Chun-Hua Liu , Kang-Shuai Li , Xiao-Zhen Yang , Yi-Jing Wang , Zhong-Liang Zhu , Zhi-Gang Xu , Sheng Zhang , Chuan Wang , You-Chen Song , Wei-Dong Zhao , Chang-He Wang , Zhi-Liang Ji , Zhong-Yin Zhang , Min Cui , Jin-Peng Sun , Xiao Yu

Tyrosine phosphorylation of secretion machinery proteins is a crucial regulatory mechanism for exocytosis. However, the participation of protein tyrosine phosphatases (PTPs) in different exocytosis stages has not been defined. Here we demonstrated that PTP-MEG2 controls multiple steps of catecholamine secretion. Biochemical and crystallographic analyses revealed key residues that the interactions between govern the PTP-MEG2 and NSF-pY83 site, specify PTP-MEG2 substrate selectivity and modulate the fusion of catecholamine-containing vesicles. Unexpectedly, delineation of PTP-MEG2 mutants along with the NSF binding interface revealed that PTP-MEG2 controls the fusion pore opening through non-NSF dependent mechanisms. Utilizing bioinformatics search and biochemical and electrochemical screening approaches, we discovered that PTP-MEG2 regulates the opening and extension of the fusion pore by dephosphorylating the DYNAMIN2-pY125 and MUNC18-1-pY145 site. Further structural and biochemical analysis confirmed the interaction of PTP-MEG2 with MUNC18-1-pY145 or DYNAMIN2-pY125 through a distinct structural basis compared with that of the NSF-pY83 site. Our studies extended mechanistic insights in complex exocytosis processes.

中文翻译:

PTP-MEG2通过两个不同的结构基础和底物调节定量大小和融合孔的开放

分泌机器蛋白的酪氨酸磷酸化是胞吐作用的关键调节机制。但是,尚未定义蛋白质酪氨酸磷酸酶(PTP)在不同胞吐阶段的参与。在这里,我们证明了PTP-MEG2控制儿茶酚胺分泌的多个步骤。生化和晶体学分析揭示了关键残基,它们之间的相互作用决定了PTP-MEG2和NSF-pY 83位点,指定PTP-MEG2底物选择性,并调节含儿茶酚胺的囊泡的融合。出乎意料的是,对PTP-MEG2突变体与NSF结合界面的描述揭示了PTP-MEG2通过非NSF依赖性机制控制融合孔的开放。利用生物信息学搜索以及生物化学和电化学筛选方法,我们发现PTP-MEG2通过使DYNAMIN2-pY 125和MUNC18-1-pY 145位去磷酸化来调节融合孔的开放和延伸。进一步的结构和生化分析证实,与NSF-pY 83相比,PTP-MEG2与MUNC18-1-pY 145或DYNAMIN2-pY 125的相互作用具有独特的结构基础现场。我们的研究在复杂的胞吐过程中扩展了机制的见解。
更新日期:2020-09-20
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