Department of Biology/Chemistry, Division of Animal Physiology, University of Osnabrück, 49076 Osnabrück, Germany
Department of Biology/Chemistry, Division of Animal Physiology, University of Osnabrück, 49076 Osnabrück, Germany.
Biochem J. 2018 Oct 22;475(20):3239-3254. doi: 10.1042/BCJ20180293.
The (SLC45) was defined in the course of the Human Genome Project and consists of four members, A1-A4, which show only 20-30% identity of amino acid sequences among each other. All these members exhibit an identity of ∼20% to plant H/sucrose cotransporters. Recently, we expressed members of the murine SLC45 family in yeast cells and demonstrated that they are, like their plant counterparts, H/sucrose cotransporters. In contrast with the plant proteins, SLC45 transporters recognise also the monosaccharides glucose and fructose as physiological substrates and seem to be involved in alternative sugar supply as well as in osmoregulation of several mammalian tissues. In the present study, we provide novel insights into the regulation of SLC45 transporters. By screening for interaction partners, we found a 14-3-3 protein as a promising candidate for control of transport activity. Indeed, co-expression of the gamma isoform of murine 14-3-3 protein in yeast and oocytes led to a significant decrease in transport rates of the murine SLC45 transporters as well as of the plant H/sucrose transporter Sut1.
(SLC45) 在人类基因组计划的过程中被定义，由四个成员 A1-A4 组成，它们彼此之间的氨基酸序列只有 20-30%的同源性。所有这些成员与植物 H/蔗糖共转运蛋白的同源性约为 20%。最近，我们在酵母细胞中表达了鼠 SLC45 家族的成员，并证明它们与植物对应物一样，是 H/蔗糖共转运蛋白。与植物蛋白不同，SLC45 转运蛋白还识别单糖葡萄糖和果糖作为生理底物，并且似乎参与替代糖供应以及几种哺乳动物组织的渗透调节。在本研究中，我们提供了 SLC45 转运蛋白调节的新见解。通过筛选相互作用伙伴，我们发现 14-3-3 蛋白是控制转运活性的有希望的候选物。事实上，在酵母和卵母细胞中共同表达鼠 14-3-3 蛋白的γ同工型导致鼠 SLC45 转运蛋白以及植物 H/蔗糖转运蛋白 Sut1 的转运速率显著降低。
