Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar 4710-057 Braga, Portugal.
Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar 4710-057 Braga, Portugal.
FEMS Yeast Res. 2021 Jan 16;21(1). doi: 10.1093/femsyr/foaa070.
The Saccharomyces cerevisiae MBOAT O-acyltransferase Gup1 is involved in many processes, including cell wall and membrane composition and integrity, and acetic acid-induced cell death. Gup1 was previously shown to interact physically with the mitochondrial membrane VDAC (Voltage-Dependent Anion Channel) protein Por1 and the ammonium transceptor Mep2. By co-immunoprecipitation, the eisosome core component Pil1 was identified as a novel physical interaction partner of Gup1. The expression of PIL1 and Pil1 protein levels were found to be unaffected by GUP1 deletion. In ∆gup1 cells, Pil1 was distributed in dots (likely representing eisosomes) in the membrane, identically to wt cells. However, ∆gup1 cells presented 50% less Pil1-GFP dots/eisosomes, suggesting that Gup1 is important for eisosome formation. The two proteins also interact genetically in the maintenance of cell wall integrity, and during arsenite and acetic acid exposure. We show that Δgup1 Δpil1 cells take up more arsenite than wt and are extremely sensitive to arsenite and to acetic acid treatments. The latter causes a severe apoptotic wt-like cell death phenotype, epistatically reverting the ∆gup1 necrotic type of death. Gup1 and Pil1 are thus physically, genetically and functionally connected.
酿酒酵母 MBOAT O-酰基转移酶 Gup1 参与许多过程，包括细胞壁和膜组成和完整性，以及乙酸诱导的细胞死亡。先前的研究表明，Gup1 与线粒体膜 VDAC（电压依赖性阴离子通道）蛋白 Por1 和铵转运体 Mep2 有物理相互作用。通过共免疫沉淀，鉴定出 eisosome 核心成分 Pil1 是 Gup1 的一个新的物理相互作用伙伴。PIL1 的表达和 Pil1 蛋白水平不受 GUP1 缺失的影响。在 ∆gup1 细胞中，Pil1 呈点状分布（可能代表 eisosomes）在膜中，与 wt 细胞相同。然而，∆gup1 细胞中 Pil1-GFP 点/ eisosomes 减少了 50%，表明 Gup1 对 eisosome 的形成很重要。这两种蛋白质在细胞壁完整性的维持和砷酸盐和乙酸暴露过程中也存在遗传相互作用。我们表明，∆gup1 Δpil1 细胞比 wt 细胞吸收更多的砷酸盐，并且对砷酸盐和乙酸处理极其敏感。后者导致严重的凋亡 wt 样细胞死亡表型，使 ∆gup1 坏死型死亡发生遗传逆转。因此，Gup1 和 Pil1 在物理、遗传和功能上是相互关联的。
