Sept8 controls the binding of vesicle-associated membrane protein 2 to synaptophysin
Sept8 controls the binding of vesicle-associated membrane protein 2 to synaptophysin
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DOI：
10.1111/j.1471-4159.2008.05849.x
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发表时间：
2009-02-01
影响因子：
4.7
通讯作者：
Nagata, Koh-ichi
中科院分区：
文献类型：
--
作者：
Ito, Hidenori;Atsuzawa, Kimie;Nagata, Koh-ichi
Septins是一个保守的GTP/GDP结合蛋白家族，存在于酵母和哺乳动物等多种生物体中。我们通过蛋白质印迹分析分析了5种septins，Sept 6，Sept 7，Sept 8，Sept 9和Sept 11，在各种大鼠组织中的分布，发现所有septins都在脑中表达。我们还研究了这些septins在大鼠脑中表达的发育变化，发现Sept 8的水平在出生后发育过程中增加。形态学分析显示，Sept 8在突触前富集。使用酵母双杂交筛选，我们在9月8日鉴定出囊泡相关膜蛋白2（VAMP 2）（一种可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体（SNARE））作为相互作用蛋白。据报道，突触体蛋白与VAMP 2缔合并将VAMP 2募集至突触囊泡，并且在形成由VAMP 2、突触融合蛋白和25 kDa的突触体相关蛋白组成的SNARE复合物之前解离。我们发现Sept 8通过与VAMP 2结合抑制VAMP 2和突触素之间的相互作用。此外，我们发现Sept 8与syntaxin 1A形成复合物，并且Sept 8-VAMP 2相互作用被25 kDa的突触体相关蛋白破坏。这些结果表明，Sept 8可能参与了SNARE复合物的形成和随后的神经递质释放过程。
Septins, a conserved family of GTP/GDP-binding proteins, are present in organisms as diverse as yeast and mammals. We analyzed the distribution of five septins, Sept6, Sept7, Sept8, Sept9 and Sept11, in various rat tissues by western blot analyses and found all septins to be expressed in brain. We also examined the developmental changes of expression of these septins in the rat brain and found that the level of Sept8 increased during post-natal development. Morphological analyses revealed that Sept8 is enriched at pre-synapses. Using yeast two-hybrid screening, we identified vesicle-associated membrane protein 2 (VAMP2), a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE), as an interacting protein for Sept8. Synaptophysin is reported to associate with and recruit VAMP2 to synaptic vesicles and dissociate prior to forming the SNARE complex consisting of VAMP2, syntaxin and synaptosome-associated protein of 25 kDa. We showed that Sept8 suppresses the interaction between VAMP2 and synaptophysin through binding to VAMP2. In addition, we found that Sept8 forms a complex with syntaxin1A, and the Sept8-VAMP2 interaction is disrupted by synaptosome-associated protein of 25 kDa. These results suggest that Sept8 may participate in the process of the SNARE complex formation and subsequent neurotransmitter release.