Roberg K J, Rowley N, Kaiser C A
Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Cell Biol. 1997 Jun 30;137(7):1469-82. doi: 10.1083/jcb.137.7.1469.
In mammalian cells, extracellular signals can regulate the delivery of particular proteins to the plasma membrane. We have discovered a novel example of regulated protein sorting in the late secretory pathway of Saccharomyces cerevisiae. In yeast cells grown on either ammonia or urea medium, the general amino acid permease (Gap1p) is transported from the Golgi complex to the plasma membrane, whereas, in cells grown on glutamate medium, Gap1p is transported from the Golgi to the vacuole. We have also found that sorting of Gap1p in the Golgi is controlled by SEC13, a gene previously shown to encode a component of the COPII vesicle coat. In sec13 mutants grown on ammonia, Gap1p is transported from the Golgi to the vacuole, instead of to the plasma membrane. Deletion of PEP12, a gene required for vesicular transport from the Golgi to the prevacuolar compartment, counteracts the effect of the sec13 mutation and partially restores Gap1p transport to the plasma membrane. Together, these studies demonstrate that both a nitrogen-sensing mechanism and Sec13p control Gap1p transport from the Golgi to the plasma membrane.
在哺乳动物细胞中，细胞外信号可调节特定蛋白质向质膜的转运。我们在酿酒酵母的晚期分泌途径中发现了一种受调控的蛋白质分选新实例。在以氨或尿素为培养基生长的酵母细胞中，通用氨基酸通透酶（Gap1p）从高尔基体转运至质膜，而在以谷氨酸为培养基生长的细胞中，Gap1p则从高尔基体转运至液泡。我们还发现，Gap1p在高尔基体中的分选受SEC13控制，SEC13是一个先前已证明编码COPII囊泡衣被成分的基因。在以氨为培养基生长的sec13突变体中，Gap1p从高尔基体转运至液泡，而非质膜。缺失PEP12（从高尔基体到前液泡区室的囊泡运输所需的基因）可抵消sec13突变的作用，并部分恢复Gap1p向质膜的转运。这些研究共同表明，氮传感机制和Sec13p都控制着Gap1p从高尔基体到质膜的转运。
