A multispecificity syntaxin homologue, Vam3p, essential for autophagic and biosynthetic protein transport to the vacuole.
A multispecificity syntaxin homologue, Vam3p, essential for autophagic and biosynthetic protein transport to the vacuole.
复制标题
多特异性语法同源物，VAM3P，对于自噬和生物合成蛋白传输到液泡必不可少。
DOI：
10.1083/jcb.138.3.517
复制
发表时间：
1997-08-11
影响因子：
7.8
通讯作者：
Emr, SD
中科院分区：
文献类型：
--
作者：
Darsow, T;Rieder, SE;Emr, SD
真核细胞中的蛋白质运输需要运输中间产物与适当的靶膜选择性对接和融合。T-SNARE分子可以通过与囊泡膜上特定的v-SNARE分子相互作用，作为运输囊泡对接和膜融合的受体，提供这些反应的固有特异性。VAM3编码一个283个氨基酸的蛋白质，它与t-SNARE分子的Synaxin家族有同源性。针对Vam3p制备的多克隆抗血清通过亚细胞分级识别与液泡膜相关的35kD蛋白。Vam3的零突变体在多个空泡蛋白的成熟过程中存在缺陷，并且含有大量异常的膜封闭的隔室。为了研究Vam3p的主要功能，我们构建了一个温度敏感的等位基因(Vam3tsf)。当将突变细胞转移到不允许的温度时，观察到通过两种不同的生物合成途径向液泡运输蛋白质的立即受阻：通过羧基肽酶Y途径和碱性磷酸酶途径的运输都被抑制。此外，细胞自噬功能也存在缺陷。在高温下，氨基肽酶I的传递和自噬小体与液泡的对接/融合都有缺陷。随着温度的变化，细胞中出现了新的膜室，包括可能代表被阻断的转运中间产物的多囊泡小体。VAM3和Sec1家族成员VPS33之间的遗传相互作用表明，这两个蛋白可能共同作用，指导多种运输中间产物与液泡的对接和/或融合。因此，Vam3p似乎在异型膜对接和与液泡的融合反应中发挥了多特异性受体的作用。令人惊讶的是，我们还发现过表达内体t-SNARE，Pep12p，抑制了Vam3Δ突变表型，同样，过表达Vam3p抑制了Pep12Δ突变表型。这一结果表明，SNARS本身并不能定义囊泡对接反应的特异性。
Protein transport in eukaryotic cells requires the selective docking and fusion of transport intermediates with the appropriate target membrane. t-SNARE molecules that are associated with distinct intracellular compartments may serve as receptors for transport vesicle docking and membrane fusion through interactions with specific v-SNARE molecules on vesicle membranes, providing the inherent specificity of these reactions. VAM3 encodes a 283–amino acid protein that shares homology with the syntaxin family of t-SNARE molecules. Polyclonal antiserum raised against Vam3p recognized a 35-kD protein that was associated with vacuolar membranes by subcellular fractionation. Null mutants of vam3 exhibited defects in the maturation of multiple vacuolar proteins and contained numerous aberrant membrane-enclosed compartments. To study the primary function of Vam3p, a temperature-sensitive allele of vam3 was generated (vam3tsf). Upon shifting the vam3tsf mutant cells to nonpermissive temperature, an immediate block in protein transport through two distinct biosynthetic routes to the vacuole was observed: transport via both the carboxypeptidase Y pathway and the alkaline phosphatase pathway was inhibited. In addition, vam3tsf cells also exhibited defects in autophagy. Both the delivery of aminopeptidase I and the docking/ fusion of autophagosomes with the vacuole were defective at high temperature. Upon temperature shift, vam3tsf cells accumulated novel membrane compartments, including multivesicular bodies, which may represent blocked transport intermediates. Genetic interactions between VAM3 and a SEC1 family member, VPS33, suggest the two proteins may act together to direct the docking and/or fusion of multiple transport intermediates with the vacuole. Thus, Vam3p appears to function as a multispecificity receptor in heterotypic membrane docking and fusion reactions with the vacuole. Surprisingly, we also found that overexpression of the endosomal t-SNARE, Pep12p, suppressed vam3Δ mutant phenotypes and, likewise, overexpression of Vam3p suppressed the pep12Δ mutant phenotypes. This result indicated that SNAREs alone do not define the specificity of vesicle docking reactions.
登录
查看更多内容
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
发表时间：
1995-04
期刊：
The Journal of cell biology
影响因子：
--
作者：
Garcia EP;McPherson PS;Chilcote TJ;Takei K;De Camilli P
通讯作者：
De Camilli P
影响因子：
64.5
作者：
BENNETT, MK;GARCIAARRARAS, JE;SCHELLER, RH
通讯作者：
SCHELLER, RH
影响因子：
3.3
作者：
Burd, CG;Peterson, M;Emr, SD
通讯作者：
Emr, SD
信号介导的膜蛋白从高尔基体中的膜蛋白回收到酵母中的ER。
DOI：
10.1083/jcb.127.3.653
发表时间：
1994-11
期刊：
The Journal of cell biology
影响因子：
--
作者：
Gaynor EC;te Heesen S;Graham TR;Aebi M;Emr SD
通讯作者：
Emr SD
酵母自噬过程的超微结构分析：自噬体的检测及其表征。
影响因子：
7.8
作者：
Baba, M;Takeshige, K;Baba, N;Ohsumi, Y
通讯作者：
Ohsumi, Y