FATTY ACYLATION IS IMPORTANT BUT NOT ESSENTIAL FOR SACCHAROMYCES-CEREVISIAE RAS FUNCTION
FATTY ACYLATION IS IMPORTANT BUT NOT ESSENTIAL FOR SACCHAROMYCES-CEREVISIAE RAS FUNCTION
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DOI：
10.1128/mcb.7.7.2344
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发表时间：
1987-07-01
影响因子：
5.3
通讯作者：
BROACH, JR
中科院分区：
文献类型：
--
作者：
DESCHENES, RJ;BROACH, JR
酿酒酵母中由 RAS1 和 RAS2 基因编码的两种蛋白质在结构和功能上与哺乳动物 ras 癌基因家族的蛋白质同源。我们通过在位于蛋白质羧基末端的假定棕榈酸酯添加位点中创建突变体，研究了脂肪酰化在酵母 RAS2 蛋白质成熟中的作用。两种突变，Cys-318 突变为蛋白石终止密码子，Cys-319 突变为 Ser-319，是在体外产生的，并在染色体中取代了正常的 RAS2 等位基因。这些变化导致 RAS2 蛋白无法被棕榈酸酯酰化，并且 RAS2 蛋白无法定位到膜部分。就所得突变体在不可发酵碳源上生长和补充ras1-突变体的能力而言，突变产生了Ras2-表型。然而，ras2Ser-319 产物的过表达产生了 Ras+ 表型，而突变蛋白与膜部分没有相应的关联。我们得出的结论是，脂肪酰基部分的存在对于将 RAS2 蛋白定位到具有活性的膜上非常重要，但脂肪酰基基团并不是 RAS2 蛋白功能的绝对要求。
Two proteins in the yeast Saccharomyces cerevisiae that are encoded by the genes RAS1 and RAS2 are structurally and functionally homologous to proteins of the mammalian ras oncogene family. We examined the role of fatty acylation in the maturation of yeast RAS2 protein by creating mutants in the putative palmitate addition site located at the carboxyl terminus of the protein. Two mutations, Cys-318 to an opal termination codon and Cys-319 to Ser-319, were created in vitro and substituted in the chromosome in place of the normal RAS2 allele. These changes resulted in a failure of RAS2 protein to be acylated with palmitate and a failure of RAS2 protein to be localized to a membrane fraction. The mutations yielded a Ras2- phenotype with respect to the ability of the resultant mutants to grow on nonfermentable carbon sources and to complement ras1- mutants. However, overexpression of the ras2Ser-319 product yielded a Ras+ phenotype without a corresponding association of the mutant protein with the membrane fraction. We conclude that the presence of a fatty acyl moiety is important for localizing RAS2 protein to the membrane where it is active but that the fatty acyl group is not an absolute requirement of RAS2 protein function.