The Sec1/Munc18 protein, Vps33p, functions at the endosome and the vacuole of Saccharomyces cerevisiae.
The Sec1/Munc18 protein, Vps33p, functions at the endosome and the vacuole of Saccharomyces cerevisiae.
复制标题
Sec1/Munc18 蛋白 Vps33p 在酿酒酵母的内体和液泡中发挥作用。
DOI：
10.1091/mbc.e03-10-0767
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发表时间：
2004
影响因子：
3.3
通讯作者：
Jones,ElizabethW
中科院分区：
文献类型：
--
作者：
Subramanian,Shoba;Woolford,CarolA;Jones,ElizabethW
Sec 1/Munc 18（SM）蛋白家族被认为赋予囊泡融合反应的区室特异性。在这里，我们报告了Vps 33 p的特征，Vps 33 p是SM家族成员，此前被认为仅与液泡突触融合蛋白Vam 3 p一起作用于液泡膜。vps 33 Δ细胞的核仁形态类似于缺乏Vam 3 p和内体突触融合蛋白Pep 12 p的细胞，这表明Vps 33 p可能与这些突触融合蛋白在液泡和内体发挥作用。与此一致，vps 33突变体分泌高尔基体前体形式的液泡水解酶CPY到培养基中。我们还证明了Vps 33 p在其他步骤中起作用，因为Vps 33突变体在晚期内体的内吞作用中表现出严重缺陷。在内体，Vps 33 p和其他C类成员作为与Vps 8 p的复合物存在，Vps 8 p是先前已知在晚期高尔基体和内体之间的运输中起作用的蛋白质。Vps 33 p也与Pep 12 p相互作用，Pep 12 p是SM蛋白Vps 45 p的已知相互作用物。高拷贝PEP 7/VAC 1抑制vps 33突变体的空泡形态缺陷。这些发现表明，Vps 33 p的功能在多个运输步骤，并不限于在液泡膜的行动。这是第一份报告表明，在同一个细胞器的两个SM蛋白的参与一个单一的syntaxin。
The Sec1/Munc18 (SM) family of proteins is thought to impart compartmental specificity to vesicle fusion reactions. Here we report characterization of Vps33p, an SM family member previously thought to act exclusively at the vacuolar membrane with the vacuolar syntaxin Vam3p. Vacuolar morphology ofvps33Δ cells resembles that of cells lacking both Vam3p and the endosomal syntaxin Pep12p, suggesting that Vps33p may function with these syntaxins at the vacuole and the endosome. Consistent with this,vps33mutants secrete the Golgi precursor form of the vacuolar hydrolase CPY into the medium. We also demonstrate that Vps33p acts at other steps, forvps33mutants show severe defects in endocytosis at the late endosome. At the endosome, Vps33p and other class C members exist as a complex with Vps8p, a protein previously known to act in transport between the late Golgi and the endosome. Vps33p also interacts with Pep12p, a known interactor of the SM protein Vps45p. High copyPEP7/VAC1suppresses vacuolar morphology defects ofvps33mutants. These findings demonstrate that Vps33p functions at multiple trafficking steps and is not limited to action at the vacuolar membrane. This is the first report demonstrating the involvement of a single syntaxin with two SM proteins at the same organelle.