Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Cell Res. 2009 Dec;19(12):1334-49. doi: 10.1038/cr.2009.130. Epub 2009 Nov 24.
The retromer is a protein complex that mediates retrograde transport of transmembrane cargoes from endosomes to the trans-Golgi network (TGN). It is comprised of a cargo-selection subcomplex of Vps26, Vps29 and Vps35 and a membrane-binding coat subcomplex of sorting nexins (SNXs). Previous studies identified SNX1/2 as one of the components of the SNX subcomplex, and SNX5/6 as candidates for the second SNX. How the retromer-associated cargoes are recognized and transported by molecular motors are largely unknown. In this study, we found that one of SNX1/2's dimerization partners, SNX6, interacts with the p150(Glued) subunit of the dynein/dynactin motor complex. We present evidence that SNX6 is a component of the retromer, and that recruitment of the motor complex to the membrane-associated retromer requires the SNX6-p150(Glued) interaction. Disruption of the SNX6-p150(Glued) interaction causes failure in formation and detachment of the tubulovesicular sorting structures from endosomes and results in block of CI-MPR retrieval from endosomes to the TGN. These observations indicate that in addition to SNX1/2, SNX6 in association with the dynein/dynactin complex drives the formation and movement of tubular retrograde intermediates.
回转体是一种蛋白复合物,介导跨膜货物从内体逆行转运到反式高尔基体网络(TGN)。它由 Vps26、Vps29 和 Vps35 的货物选择亚基和分选连接蛋白(SNXs)的膜结合外壳亚基组成。先前的研究鉴定出 SNX1/2 是 SNX 亚基复合物的一个组成部分,而 SNX5/6 是第二个 SNX 的候选物。回转体相关货物如何被分子马达识别和运输在很大程度上是未知的。在这项研究中,我们发现 SNX1/2 的二聚化伴侣之一 SNX6 与动力蛋白/动力蛋白复合物的 p150(Glued)亚基相互作用。我们提供的证据表明,SNX6 是回转体的一个组成部分,并且马达复合物被招募到膜相关的回转体需要 SNX6-p150(Glued)相互作用。SNX6-p150(Glued)相互作用的破坏导致从内体形成和分离管状囊泡状分选结构失败,并导致 CI-MPR 从内体到 TGN 的回收受阻。这些观察结果表明,除了 SNX1/2 之外,与动力蛋白/动力蛋白复合物相关的 SNX6 驱动管状逆行中间体的形成和运动。