Calcium release through P2X4 activates calmodulin to promote endolysosomal membrane fusion.
Calcium release through P2X4 activates calmodulin to promote endolysosomal membrane fusion.
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DOI：
10.1083/jcb.201409071
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发表时间：
2015-06-22
期刊：
影响因子：
--
通讯作者：
Dong XP
中科院分区：
文献类型：
--
作者：
Cao Q;Zhong XZ;Zou Y;Murrell-Lagnado R;Zhu MX;Dong XP
P2X4和钙调蛋白在晚期内体和溶酶体中形成信号复合物，其以Ca2+依赖性方式促进融合和空泡化。内溶酶体内Ca2+释放是内溶酶体膜与细胞内细胞器融合所必需的。然而，内溶酶体Ca2+释放的分子机制和下游Ca2+融合涉及的目标仍然难以捉摸。以前，我们证明了内溶酶体P2X4形成通道激活的管腔腺苷三磷酸在pH值依赖性的方式。在本文中，我们表明，P2X4的过表达，以及增加内溶酶体P2X4活性的碱化内溶酶体腔，促进空泡扩大细胞和内溶酶体融合在无细胞测定。通过抑制P2X4、表达显性负性P2X4突变体和破坏P2X4基因来防止这些效应。我们进一步表明，P2X4和钙调蛋白（CaM）形成一个复杂的内溶酶体膜，P2X4激活招聘钙调蛋白，以促进融合和空泡化的钙离子依赖的方式。此外，P2X4激活触发的融合和空泡化被抑制通过抑制钙调蛋白。因此，我们的数据表明，一个新的分子机制，涉及P2X4介导的内溶酶体膜融合Ca2+的释放和随后的钙调素激活。
P2X4 and calmodulin form a signaling complex in late endosomes and lysosomes that promotes fusion and vacuolation in a Ca2+-dependent fashion. Intra-endolysosomal Ca2+ release is required for endolysosomal membrane fusion with intracellular organelles. However, the molecular mechanisms for intra-endolysosomal Ca2+ release and the downstream Ca2+ targets involved in the fusion remain elusive. Previously, we demonstrated that endolysosomal P2X4 forms channels activated by luminal adenosine triphosphate in a pH-dependent manner. In this paper, we show that overexpression of P2X4, as well as increasing endolysosomal P2X4 activity by alkalinization of endolysosome lumen, promoted vacuole enlargement in cells and endolysosome fusion in a cell-free assay. These effects were prevented by inhibiting P2X4, expressing a dominant-negative P2X4 mutant, and disrupting the P2X4 gene. We further show that P2X4 and calmodulin (CaM) form a complex at endolysosomal membrane where P2X4 activation recruits CaM to promote fusion and vacuolation in a Ca2+-dependent fashion. Moreover, P2X4 activation-triggered fusion and vacuolation were suppressed by inhibiting CaM. Our data thus suggest a new molecular mechanism for endolysosomal membrane fusion involving P2X4-mediated endolysosomal Ca2+ release and subsequent CaM activation.
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影响因子：
16.6
作者：
Dong, Xian-ping;Shen, Dongbiao;Wang, Xiang;Dawson, Taylor;Li, Xinran;Zhang, Qi;Cheng, Xiping;Zhang, Yanling;Weisman, Lois S.;Delling, Markus;Xu, Haoxing
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Xu, Haoxing
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64.8
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64.5
作者：
Cang C;Zhou Y;Navarro B;Seo YJ;Aranda K;Shi L;Battaglia-Hsu S;Nissim I;Clapham DE;Ren D
通讯作者：
Ren D
影响因子：
7.7
作者：
Huynh, C;Andrews, NW
通讯作者：
Andrews, NW
影响因子：
4.8
作者：
Huang, Peng;Zou, Yuanjie;Dong, Xian-Ping
通讯作者：
Dong, Xian-Ping