rbSec1A and B colocalize with syntaxin 1 and SNAP-25 throughout the axon, but are not in a stable complex with syntaxin.
rbSec1A and B colocalize with syntaxin 1 and SNAP-25 throughout the axon, but are not in a stable complex with syntaxin.
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RBSEC1A和B与语法1和SNAP-25共同定位，但在整个轴突中都不是与语法素一起稳定的复合物。
DOI：
10.1083/jcb.129.1.105
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发表时间：
1995-04
期刊：
影响因子：
--
通讯作者：
De Camilli P
中科院分区：
文献类型：
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作者：
Garcia EP;McPherson PS;Chilcote TJ;Takei K;De Camilli P
rbSec1 是一种哺乳动物神经元蛋白，与胞吐作用所需的酵母 SEC1 基因产物同源。线虫和黑腹果蝇神经系统中 Sec1 同源物的突变导致神经递质分泌缺陷。生化研究表明，重组 rbSec1 结合突触结合蛋白 1，但不结合 SNAP-25 或 synaptobrevin/VAMP，这两种蛋白与突触结合蛋白 1 一起形成突触 SNARE 复合体。在这项研究中，我们检查了 rbSec1 的亚细胞定位以及 rbSec1 和 Syntaxin 1 之间的原位相互作用程度。 rbSec1，我们在这里显示为由两个选择性剪接的亚型 rbSec1A 和 B 代表，在轴突中广泛分布，并且不限于神经末梢。这种分布与突触蛋白 1 和 SNAP-25 沿整个轴突质膜的定位平行。 rbSec1 以可溶性和膜相关形式存在。尽管质膜上存在大量 rbSec1，但大多数膜结合 rbSec1 与突触蛋白 1 无关。我们还表明，rbSec1 不是突触 SNARE 复合体的一部分，也不是我们发现存在于轴突非突触区域的突触蛋白 1/SNAP-25 复合体的一部分。因此，尽管生化研究证明 rbSec1 和 Syntaxin 1 具有高亲和力相互作用，但我们的结果表明 rbSec1 和 Syntaxin 1 并不稳定相关。他们还表明，rbSec1、syntaxin 1 和 SNAP-25 的功能并不局限于突触处的突触小泡胞吐作用。
rbSec1 is a mammalian neuronal protein homologous to the yeast SEC1 gene product which is required for exocytosis. Mutations in Sec1 homologues in the nervous systems of C. elegans and D. melanogaster lead to defective neurotransmitter secretion. Biochemical studies have shown that recombinant rbSec1 binds syntaxin 1 but not SNAP-25 or synaptobrevin/VAMP, the two proteins which together with syntaxin 1 form the synaptic SNARE complex. In this study we have examined the subcellular localization of rbSec1 and the degree of interaction between rbSec1 and syntaxin 1 in situ. rbSec1, which we show here to be represented by two alternatively spliced isoforms, rbSec1A and B, has a widespread distribution in the axon and is not restricted to the nerve terminal. This distribution parallels the localization of syntaxin 1 and SNAP-25 along the entire axonal plasmalemma. rbSec1 is found in a soluble and a membrane-associated form. Although a pool of rbSec1 is present on the plasmalemma, the majority of membrane-bound rbSec1 is not associated with syntaxin 1. We also show that rbSec1 is not part of the synaptic SNARE complex or of the syntaxin 1/SNAP-25 complex we show to be present in non-synaptic regions of the axon. Thus, in spite of biochemical studies demonstrating the high affinity interaction of rbSec1 and syntaxin 1, our results indicate that rbSec1 and syntaxin 1 are not stably associated. They also suggest that the function of rbSec1, syntaxin 1, and SNAP-25 is not restricted to synaptic vesicle exocytosis at the synapse.