Sherwood P W, Carlson M
Department of Genetics and Development, Columbia University, New York, NY 10032, USA.
Proc Natl Acad Sci U S A. 1999 Jun 22;96(13):7415-20. doi: 10.1073/pnas.96.13.7415.
Mutations in the GSF2 gene cause glucose starvation phenotypes in Saccharomyces cerevisiae. We have isolated the HXT1 gene, which encodes a low-affinity, high-capacity glucose transporter, as a multicopy suppressor of a gsf2 mutation. We show that gsf2 mutants accumulate Hxt1p in the endoplasmic reticulum (ER) and that Gsf2p is a 46-kDa integral membrane protein localized to the ER. gsf2 mutants also display a galactose growth defect and abnormal localization of the galactose transporter Gal2p but are not defective in function or localization of the high-affinity glucose transporter Hxt2p. These findings suggest that Gsf2p functions in the ER to promote the secretion of certain hexose transporters.
GSF2基因突变会导致酿酒酵母出现葡萄糖饥饿表型。我们分离出了HXT1基因,它编码一种低亲和力、高容量的葡萄糖转运蛋白,作为gsf2突变的多拷贝抑制子。我们发现gsf2突变体在内质网(ER)中积累Hxt1p,并且Gsf2p是一种定位于内质网的46 kDa整合膜蛋白。gsf2突变体还表现出半乳糖生长缺陷以及半乳糖转运蛋白Gal2p的定位异常,但高亲和力葡萄糖转运蛋白Hxt2p的功能或定位没有缺陷。这些发现表明,Gsf2p在内质网中发挥作用,促进某些己糖转运蛋白的分泌。