Foley Deirdre A, Sharpe Hayley J, Otte Stefan
Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Illinois, USA.
Mol Membr Biol. 2007 Jul-Aug;24(4):259-68. doi: 10.1080/09687860601178518.
Secretory proteins are transported from the endoplasmic reticulum to the Golgi apparatus via COPII-coated intermediates. Yeast Erv29p is a transmembrane protein cycling between these compartments. It is conserved across species, with one ortholog found in each genome studied, including the surf-4 protein in mammals. Yeast Erv29p acts as a receptor, loading a specific subset of soluble cargo, including glycosylated alpha factor pheromone precursor and carboxypeptidase Y, into vesicles. As the eukaryotic secretory pathway is highly conserved, mammalian surf-4 may perform a similar role in the transport of unknown substrates. Here we report the membrane topology of yeast Erv29p, which we solved by minimally invasive cysteine accessibility scanning using thiol-specific biotinylation and fluorescent labeling methods. Erv29p contains four transmembrane domains with both termini exposed to the cytosol. Two luminal loops may contain a recognition site for hydrophobic export signals on soluble cargo.
分泌蛋白通过COPII包被的中间体从内质网运输到高尔基体。酵母Erv29p是一种在这些区室之间循环的跨膜蛋白。它在物种间保守，在所研究的每个基因组中都发现了一个直系同源物，包括哺乳动物中的surf-4蛋白。酵母Erv29p作为一种受体，将特定的可溶性货物子集，包括糖基化的α因子信息素前体和羧肽酶Y，装载到囊泡中。由于真核生物分泌途径高度保守，哺乳动物surf-4可能在未知底物的运输中发挥类似作用。在此我们报告酵母Erv29p的膜拓扑结构，我们通过使用硫醇特异性生物素化和荧光标记方法的微创半胱氨酸可及性扫描来解析该结构。Erv29p包含四个跨膜结构域，其两端都暴露于胞质溶胶。两个腔内环可能包含可溶性货物上疏水输出信号的识别位点。
