Finger F P, Hughes T E, Novick P
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8002, USA.
Cell. 1998 Feb 20;92(4):559-71. doi: 10.1016/s0092-8674(00)80948-4.
Exocytosis in yeast occurs at plasma membrane subdomains whose locations vary with the cell cycle, but the primary protein determinants of these sites are unknown. A functional fusion of Sec3 protein with green fluorescent protein (Sec3-GFP) localizes to the site of polarized exocytosis for each cell-cycle stage, where it colocalizes with Sec4p and Sec8p. Sec3-GFP localization is independent of secretory pathway function, of the actin and septin cytoskeletons, and of the polarity establishment proteins. We propose that Sec3p is a spatial landmark defining sites of exocytosis. Polarized secretion would result from the coupling of actin-dependent vesicle targeting with Sec3p-dependent establishment of the vesicle fusion site.
酵母中的胞吐作用发生在质膜亚结构域，其位置随细胞周期而变化，但这些位点的主要蛋白质决定因素尚不清楚。Sec3蛋白与绿色荧光蛋白的功能性融合体（Sec3-GFP）定位于每个细胞周期阶段的极化胞吐作用位点，在那里它与Sec4p和Sec8p共定位。Sec3-GFP的定位独立于分泌途径功能、肌动蛋白和隔膜细胞骨架以及极性建立蛋白。我们提出Sec3p是定义胞吐作用位点的空间标志物。极化分泌将由肌动蛋白依赖性囊泡靶向与Sec3p依赖性囊泡融合位点的建立耦合产生。
