Graham T R, Scott P A, Emr S D
Howard Hughes Medical Institute, University of California, San Diego, School of Medicine, La Jolla 92093-0668.
EMBO J. 1993 Mar;12(3):869-77. doi: 10.1002/j.1460-2075.1993.tb05727.x.
We have found that brefeldin A (BFA) inhibited the growth of an ise1 mutant of Saccharomyces cerevisiae. Genetic complementation and mapping studies demonstrated that ise1 was allelic to erg6, a gene required for the biosynthesis of the principal membrane sterol of yeast, ergosterol. Treatment of ise1 cells with BFA resulted in an immediate block in protein transport through the secretory pathway. Vacuolar carboxypeptidase Y (CPY) and the secreted pheromone alpha-factor accumulated as both the core glycosylated (ER) and alpha 1,6 mannosylated (early Golgi) forms in drug-treated cells. The modification of alpha-factor with alpha 1,6 mannose in BFA-treated cells did not appear to result from retrograde transport of the alpha 1,6 mannosyl-transferase into the ER. We found that transport of CPY from medial and late Golgi compartments to the vacuole was unaffected by BFA, nor was secretion of alpha 1,3 mannosylated alpha-factor or invertase blocked by BFA. The effects of BFA on the secretory pathway were also reversible after brief exposure (< 40 min) to the drug. We suggest that the primary effect of BFA in S. cerevisiae is restricted to the ER and the alpha 1,6 mannosyltransferase compartment of the Golgi complex.
我们发现布雷菲德菌素A（BFA）可抑制酿酒酵母ise1突变体的生长。遗传互补和定位研究表明，ise1与erg6等位，erg6是酵母主要膜甾醇麦角固醇生物合成所需的基因。用BFA处理ise1细胞会导致蛋白质通过分泌途径的转运立即受阻。在药物处理的细胞中，液泡羧肽酶Y（CPY）和分泌的信息素α-因子以核心糖基化（内质网）和α1,6甘露糖基化（早期高尔基体）形式积累。在BFA处理的细胞中，α-因子与α1,6甘露糖的修饰似乎并非由α1,6甘露糖基转移酶逆向转运到内质网所致。我们发现CPY从高尔基体中间和晚期区室向液泡的转运不受BFA影响，α1,3甘露糖基化的α-因子或蔗糖酶的分泌也未被BFA阻断。在短暂暴露于该药物（<40分钟）后，BFA对分泌途径的影响也是可逆的。我们认为BFA在酿酒酵母中的主要作用仅限于内质网和高尔基体复合体的α1,6甘露糖基转移酶区室。
