A RAT-BRAIN SEC1 HOMOLOG RELATED TO ROP AND UNC18 INTERACTS WITH SYNTAXIN
A RAT-BRAIN SEC1 HOMOLOG RELATED TO ROP AND UNC18 INTERACTS WITH SYNTAXIN
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DOI：
10.1073/pnas.91.6.2003
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发表时间：
1994-03-15
影响因子：
11.1
通讯作者：
DECAMILLI, P
中科院分区：
文献类型：
--
作者：
GARCIA, EP;GATTI, E;DECAMILLI, P
Sec 1是一种亲水性蛋白，在酿酒酵母的胞吐作用中起重要作用。Sec 1基因中的两个高拷贝突变抑制子SSO 1和SSO 2最近被鉴定为编码突触融合蛋白家族的蛋白质。突触融合蛋白（一种T-陷阱）与SNAP-25和小突触泡蛋白/VAMP（分别为一种T-陷阱和一种V-陷阱）一起被认为形成了突触囊泡胞吐作用中对接融合复合物的核心。在黑腹果蝇（Rop）和秀丽隐杆线虫（UNC 18）的神经系统中鉴定出与Sec 1相似的蛋白质。基于Sec 1，Rop和UNC 18的氨基酸序列比对，我们已经使用了基于PCR的方法来分离编码Sec 1同源物的大鼠脑cDNA。通过北方印迹分析，cDNA与3.5-kb脑特异性mRNA杂交，并编码593个氨基酸的蛋白质（rbSec 1）。针对rbSec 1的中心部分提出的抗体识别大鼠脑总匀浆中的67.5 kDa蛋白，但不识别非神经元组织。当与Triton X-100脑提取物孵育时，rbSec 1-谷胱甘肽S-转移酶（GST）融合蛋白（而不是单独的GST蛋白）特异性地与突触融合蛋白相互作用，但不与SNAP-25或小突触泡蛋白/VAMP相互作用。我们的结论是，Sec 1家族的蛋白质在膜融合的功能涉及与T-陷阱的相互作用。
Sec1 is a hydrophilic protein that plays an essential role in exocytosis from the yeast Saccharomyces cerevisiae. Two high copy suppressors of mutations in the Sec1 gene, SSO1 and SSO2, were recently identified that encode proteins of the syntaxin family. Syntaxin (a T-SNARE), together with SNAP-25 and synaptobrevin/VAMP (a T- and a V-SNARE, respectively), is thought to form the core of the docking-fusion complex in synaptic vesicle exocytosis. Proteins that exhibit similarity to Sec1 were identified in the nervous system of Drosophila melanogaster (Rop) and Caenorhabditis elegans (UNC18). Based on the amino acid sequence alignment of Sec1, Rop, and UNC18, we have used a PCR-based approach to isolate a rat brain cDNA encoding a Sec1 homologue. The cDNA hybridizes to a 3.5-kb brain specific mRNA by Northern blot analysis and encodes a protein of 593 amino acids (rbSec1). Antibodies raised against a central portion of rbSec1 recognize a 67.5-kDa protein in total homogenates of rat brain but not of nonneuronal tissues. When incubated with a Triton X-100 brain extract, rbSec1-glutathione S-transferase (GST) fusion protein, but not GST protein alone, specifically interacts with syntaxin but not with SNAP-25 or synaptobrevin/VAMP. We conclude that the function of proteins of the Sec1 family in membrane fusion involves an interaction with a T-SNARE.