Identification of the Neuroblastoma-amplified Gene Product as a Component of the Syntaxin 18 Complex Implicated in Golgi-to-Endoplasmic Reticulum Retrograde Transport
Identification of the Neuroblastoma-amplified Gene Product as a Component of the Syntaxin 18 Complex Implicated in Golgi-to-Endoplasmic Reticulum Retrograde Transport
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DOI：
10.1091/mbc.e08-11-1104
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发表时间：
2009-06-01
影响因子：
3.3
通讯作者：
Tagaya, Mitsuo
中科院分区：
文献类型：
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作者：
Aoki, Takehiro;Ichimura, Sarah;Tagaya, Mitsuo
突触融合蛋白18是一种可溶性N-乙基马来酰亚胺敏感因子（NSF）附着蛋白受体（SNARE）蛋白，与内质网（ER）膜融合有关，与其他SNARE（BNIP 1、p31和Sec 22 b）和几种外周膜组分（Sly 1、ZW 10和RINT-1）形成复合物。在本研究中，我们发现，外周膜蛋白编码的神经母细胞瘤扩增基因（NAG）是一个亚基的syntaxin 18复合物。NAG编码2371个氨基酸的蛋白质，其表现出与酵母Dsl 3 p/Sec 39 p的弱相似性，所述酵母Dsl 3 p/Sec 39 p是含有酵母突触融合蛋白18直向同源物Ufe 1 p的复合物的82-kDa组分。在有利于SNARE复合物分解的条件下，NAG从syntaxin 18中释放出来，但仍保留在p31-ZW 10-RINT-1亚复合物中。结合研究表明，p31的极端N-末端区域负责与NAG的相互作用，NAG的N-和C-末端区域分别与p31和ZW 10-RINT-1相互作用。敲低NAG导致p31表达减少，证实了它们的密切关系。NAG耗竭并没有实质上影响高尔基体的形态和蛋白质出口的ER，但它会导致重新分配的高尔基体回收蛋白伴随着蛋白质糖基化的缺陷。这些结果共同表明，NAG连接p31和ZW 10-RINT-1，并参与高尔基体到ER的运输。
Syntaxin 18, a soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) protein implicated in endoplasmic reticulum (ER) membrane fusion, forms a complex with other SNAREs (BNIP1, p31, and Sec22b) and several peripheral membrane components (Sly1, ZW10, and RINT-1). In the present study, we showed that a peripheral membrane protein encoded by the neuroblastoma-amplified gene (NAG) is a subunit of the syntaxin 18 complex. NAG encodes a protein of 2371 amino acids, which exhibits weak similarity to yeast Dsl3p/Sec39p, an 82-kDa component of the complex containing the yeast syntaxin 18 orthologue Ufe1p. Under conditions favoring SNARE complex disassembly, NAG was released from syntaxin 18 but remained in a p31-ZW10-RINT-1 subcomplex. Binding studies showed that the extreme N-terminal region of p31 is responsible for the interaction with NAG and that the N- and the C-terminal regions of NAG interact with p31 and ZW10-RINT-1, respectively. Knockdown of NAG resulted in a reduction in the expression of p31, confirming their intimate relationship. NAG depletion did not substantially affect Golgi morphology and protein export from the ER, but it caused redistribution of Golgi recycling proteins accompanied by a defect in protein glycosylation. These results together suggest that NAG links between p31 and ZW10-RINT-1 and is involved in Golgi-to-ER transport.