EHD3 regulates early-endosome-to-Golgi transport and preserves Golgi morphology
EHD3 regulates early-endosome-to-Golgi transport and preserves Golgi morphology
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DOI：
10.1242/jcs.037051
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发表时间：
2009-02-01
影响因子：
4
通讯作者：
Caplan, Steve
中科院分区：
文献类型：
--
作者：
Naslavsky, Naava;McKenzie, Jenna;Caplan, Steve
EHD 3的缺失通过改变受体再循环至质膜的动力学和途径来影响内体中的分选。在这里，我们证明，siRNA敲低EHD 3，或其相互作用的合作伙伴rabenosyn-5，导致重新分配的分选连接蛋白1（SNX 1）扩大早期内涵体和破坏运输内化的滋贺毒素B亚基（STx B）到高尔基体。此外，在这些条件下，高尔基体形态出现作为一系列高度分散和碎片化的堆栈，保持顺式，中间和反式高尔基体膜的特性。虽然Arf 1仍然组装在这些分散的高尔基体膜上，但AP-1 γ-适应素在高尔基体上的水平降低了。而VSV-G-分泌从分散的高尔基体在很大程度上保持不受影响，甘露糖6-磷酸受体（M6 PR）的分布被改变：它仍然在外周内体，并没有返回到高尔基体。组织蛋白酶D是一种水解酶，通常通过M6 PR依赖性途径转运到溶酶体，仍然被困在高尔基体。我们的研究结果支持EHD 3在调节内体到高尔基体运输中的作用，因此，溶酶体生物合成，但不分泌，运输途径也受到影响。这些数据还表明，受损的内体到高尔基体的运输和由此导致的缺乏AP-1 γ-适应蛋白到高尔基体膜的募集影响高尔基体形态。
Depletion of EHD3 affects sorting in endosomes by altering the kinetics and route of receptor recycling to the plasma membrane. Here we demonstrate that siRNA knockdown of EHD3, or its interaction partner rabenosyn-5, causes redistribution of sorting nexin 1 (SNX1) to enlarged early endosomes and disrupts transport of internalized Shiga toxin B subunit (STxB) to the Golgi. Moreover, under these conditions, Golgi morphology appears as a series of highly dispersed and fragmented stacks that maintain characteristics of cis-, medial- and trans-Golgi membranes. Although Arf1 still assembled onto these dispersed Golgi membranes, the level of AP-1 gamma-adaptin recruited to the Golgi was diminished. Whereas VSV-G-secretion from the dispersed Golgi remained largely unaffected, the distribution of mannose 6-phosphate receptor (M6PR) was altered: it remained in peripheral endosomes and did not return to the Golgi. Cathepsin D, a hydrolase that is normally transported to lysosomes via an M6PR-dependent pathway, remained trapped at the Golgi. Our findings support a role for EHD3 in regulating endosome-to-Golgi transport, and as a consequence, lysosomal biosynthetic, but not secretory, transport pathways are also affected. These data also suggest that impaired endosome-to-Golgi transport and the resulting lack of recruitment of AP-1 gamma-adaptin to Golgi membranes affect Golgi morphology.