Mutational analysis of the SNF3 glucose transporter of Saccharomyces cerevisiae.
Mutational analysis of the SNF3 glucose transporter of Saccharomyces cerevisiae.
复制标题
酿酒酵母 SNF3 葡萄糖转运蛋白的突变分析。
DOI：
10.1128/mcb.10.3.1105-1115.1990
复制
发表时间：
1990
影响因子：
5.3
通讯作者：
Carlson,M
中科院分区：
文献类型：
--
作者：
Marshall-Carlson,L;Celenza,JL;Laurent,BC;Carlson,M
TheSNF3gene ofSaccharomyces cerevisiaeencodes a high-affinity glucose transporter that is homologous to mammalian glucose transporters. Point mutations affecting the function of the transporter were recovered from the genomes of foursnf3mutants and characterized. Two of the mutations introduced a charged amino acid into the first and second predicted membrane-spanning regions, respectively. The analogs of a bifunctionalSNF3-lacZfusion containing these two mutations were constructed, and the mutant fusion proteins were not localized to the plasma membrane, as judged by immunofluorescence microscopy. The third mutation produced a valine-to-isoleucine substitution in hydrophobic region 8, and the corresponding mutant fusion protein was correctly localized. The finding that this conservative change causes a transport defect is consistent with the possibility that this transmembrane region, which could exist as an amphipathic α-helix, forms part of the glucose channel through the membrane. The fourthsnf3allele harbored an ochre mutation midway through the coding sequence. We have also constructed mutations in the clonedSNF3gene. A major difference between the yeast SNF3 protein and mammalian glucose transporters is the presence in the SNF3 protein of an additional 303 amino acids at the C terminus. Analysis of a series of C-terminal deletions and fusions tolacZshowed that this C-terminal region is important, but not essential, for transport function. We also report the genetic mapping of theSNF3locus on the left arm of chromosome IV.
