Cell wall and cytoskeleton reorganization as the response to hyperosmotic shock in Saccharomyces cerevisiae
Cell wall and cytoskeleton reorganization as the response to hyperosmotic shock in Saccharomyces cerevisiae
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DOI：
10.1007/s002030000136
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发表时间：
2000-04-01
影响因子：
2.8
通讯作者：
Farkas, V
中科院分区：
文献类型：
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作者：
Slaninová, I;Sesták, S;Farkas, V
将指数生长的酿酒酵母细胞转移到含有0.7-1 M KCl、1 M甘露醇和/或1 M甘油的高渗生长培养基中，导致酵母生长停止约2小时;此后，生长几乎以原始速率恢复。在此期间，观察到在用报春花素或Calcofluor白色染色的细胞壁的内表面上形成荧光斑。在KCl溶液中或用放线菌酮和/或2-脱氧葡萄糖阻断细胞壁的合成时也形成荧光斑。随着细胞恢复生长，斑块逐渐消失，新的芽具有光滑的细胞壁。冷冻蚀刻复制品的电子显微镜下显示，深质膜内陷填充从周质侧与无定形细胞壁材料，似乎对应于细胞表面上的荧光补丁。渗透压休克过程中D-[U-C-14]葡萄糖从生长培养基中掺入单个细胞壁多糖的速率遵循生长动力学。高渗休克引起的细胞骨架元素的变化，表现为微管和肌动蛋白微丝的消失。在高渗培养基中培养2-3 h后，微管和微丝均恢复到原来的极化状态，肌动蛋白片恢复到生长芽顶端的位置。S.在葡萄糖敏感途径基因HOG 1和PBS 2中具有突变的酿酒酵母菌株对高渗休克的敏感性与野生型菌株相似。我们的结论是，除了引起暂时的解体的细胞骨架，高渗休克诱导细胞壁的组织的变化，显然是由于从周质和细胞壁基质材料的位移到内陷的质膜所创建的plasma。
Transfer of exponentially growing cells of the yeast Saccharomyces cerevisiae to hyperosmotic growth medium containing 0.7-1 M KCl, 1 M mannitol, and/or 1 M glycerol caused cessation of yeast growth for about 2 h; thereafter,growth resumed at almost the original rate. During this time, formation of fluorescent patches on the inner surface of cell walls stained with Primulin or Calcofluor white was observed. The fluorescent patches also formed in solutions of KCl or when synthesis of the cell wall was blocked with cycloheximide and/or 2-deoxyglucose. The patches gradually disappeared as the cells resumed growth, and the new buds had smooth cell walls. Electron microscopy of freeze-etched replicas of osmotically stressed cells revealed deep plasma membrane invaginations filled from the periplasmic side with an amorphous cell wall material that appeared to correspond to the fluorescent patches on the cell surface. The rate of incorporation of D-[U-C-14]glucose from the growth medium into the individual cell wall polysaccharides during osmotic shock followed the growth kinetics. No differences in cell wall composition between osmotically stressed yeast and control cells were found. Hyperosmotic shock caused changes in cytoskeletal elements, as demonstrated by the disappearance of microtubules and actin microfilaments. After 2-3 h in hyperosmotic medium, both microtubules and microfilaments regenerated to their original polarized forms and the actin patches resumed their positions at the apices of growing buds. The response of S. cerevisiae strains with mutations in the osmosensing pathway genes hog1 and pbs2 to hyperosmotic shock was similar to that of the wild-type strain. We conclude that, besides causing a temporary disassembling of the cytoskeleton, hyperosmotic shock induces a change in the organization of the cell wall, apparently resulting from the displacement of periplasmic and cell wall matrix material into invaginations of the plasma membrane created by the plasmolysis.