SNAP23/25 and VAMP2 mediate exocytic event of transferrin receptor-containing recycling vesicles.
SNAP23/25 and VAMP2 mediate exocytic event of transferrin receptor-containing recycling vesicles.
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DOI：
10.1242/bio.012146
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发表时间：
2015-06-19
期刊：
影响因子：
2.4
通讯作者：
Nakayama K
中科院分区：
文献类型：
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作者：
Kubo K;Kobayashi M;Nozaki S;Yagi C;Hatsuzawa K;Katoh Y;Shin HW;Takahashi S;Nakayama K
我们最近发现Rab 11不仅参与形成含有转铁蛋白（Tfn）-转铁蛋白受体（TfnR）复合物的核周再循环内体再循环囊泡，而且还参与将再循环囊泡与外囊栓系复合物一起栓系到质膜（PM）。我们在这里的目的是确定SNARE蛋白负责融合的Tfn-TfnR的回收囊泡与PM，下游的外囊。我们发现，外囊亚基，Sec 6和Sec 8，可以与SNAP 23和SNAP 25，这两者都是PM定位Qbc-SNARE，和SNAP 23和/或SNAP 25在HeLa细胞中的耗竭抑制融合的Tfn-TfnR的囊泡与PM，导致在细胞周边的囊泡的积累。我们还发现，VAMP 2（一种R-SNARE）与内吞的Tfn共定位在点状内体结构上，并且它在HeLa细胞中的耗尽抑制了再循环囊泡的胞吐作用。这些观察结果表明，再循环囊泡与外囊下游PM的融合是由SNAP 23/25和VAMP 2介导的，并提供了对VAMP 2和SNAP 25的非神经元作用的新见解。
We recently showed that Rab11 is involved not only in formation of recycling vesicles containing the transferrin (Tfn)–transferrin receptor (TfnR) complex at perinuclear recycling endosomes but also in tethering of recycling vesicles to the plasma membrane (PM) in concert with the exocyst tethering complex. We here aimed at identifying SNARE proteins responsible for fusion of Tfn–TfnR-containing recycling vesicles with the PM, downstream of the exocyst. We showed that exocyst subunits, Sec6 and Sec8, can interact with SNAP23 and SNAP25, both of which are PM-localizing Qbc-SNAREs, and that depletion of SNAP23 and/or SNAP25 in HeLa cells suppresses fusion of Tfn–TfnR-containing vesicles with the PM, leading to accumulation of the vesicles at the cell periphery. We also found that VAMP2, an R-SNARE, is colocalized with endocytosed Tfn on punctate endosomal structures, and that its depletion in HeLa cells suppresses recycling vesicle exocytosis. These observations indicate that fusion of recycling vesicles with the PM downstream of the exocyst is mediated by SNAP23/25 and VAMP2, and provide novel insight into non-neuronal roles of VAMP2 and SNAP25.