Breinig Frank, Tipper Donald J, Schmitt Manfred J
Angewandte Molekularbiologie, Universität des Saarlandes, D-66041, Saarbrücken, Germany.
Cell. 2002 Feb 8;108(3):395-405. doi: 10.1016/s0092-8674(02)00634-7.
Saccharomyces cerevisiae K1 killer strains are infected by the M1 double-stranded RNA virus encoding a secreted protein toxin that kills sensitive cells by disrupting cytoplasmic membrane function. Toxin binding to spheroplasts is mediated by Kre1p, a cell wall protein initially attached to the plasma membrane by its C-terminal GPI anchor. Kre1p binds toxin directly. Both cells and spheroplasts of Deltakre1 mutants are completely toxin resistant; binding to cell walls and spheroplasts is reduced to 10% and < 0.5%, respectively. Expression of K28-Kre1p, an inactive C-terminal fragment of Kre1p retaining its toxin affinity and membrane anchor, fully restored toxin binding and sensitivity to spheroplasts, while intact cells remained resistant. Kre1p is apparently the toxin membrane receptor required for subsequent lethal ion channel formation.
酿酒酵母K1杀伤菌株被M1双链RNA病毒感染，该病毒编码一种分泌性蛋白毒素，通过破坏细胞质膜功能杀死敏感细胞。毒素与原生质球的结合由Kre1p介导，Kre1p是一种细胞壁蛋白，最初通过其C端糖基磷脂酰肌醇（GPI）锚定附着于质膜。Kre1p直接结合毒素。Deltakre1突变体的细胞和原生质球对毒素完全抗性；与细胞壁和原生质球的结合分别降至10%和<0.5%。K28-Kre1p是Kre1p的无活性C端片段，保留其毒素亲和力和膜锚定，完全恢复了毒素与原生质球的结合及敏感性，而完整细胞仍具抗性。Kre1p显然是后续致死性离子通道形成所需的毒素膜受体。
