A synthetic lethal screen identifies a role for the cortical actin patch/endocytosis complex in the response to nutrient deprivation in Saccharomyces cerevisiae
A synthetic lethal screen identifies a role for the cortical actin patch/endocytosis complex in the response to nutrient deprivation in Saccharomyces cerevisiae
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DOI：
10.1534/genetics.166.2.707
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发表时间：
2004-02-01
期刊：
影响因子：
3.3
通讯作者：
Sudbery, PE
中科院分区：
文献类型：
--
作者：
Care, A;Vousden, KA;Sudbery, PE
酿酒酵母（Saccharomyces cerevisiae）的2delta细胞在营养限制下不能停止细胞分裂，并且对各种各样的应激敏感。合成致死筛选分离出了si6个表型与wh2delta相似的突变体。其中包括影响SIW14、FEN2、SLT2和THR4的突变。在wh2delta、siw14Delta、fen2Delta和thr4Delta突变体中，液相内吞作用严重减少或消失。此外，wh2delta和siw14Delta突变体在固定期产生大的肌动蛋白团块，类似于prk1Delta突变体在调节肌动蛋白细胞骨架的蛋白激酶缺陷中所看到的。SIW14在prk1Delta菌株中的过表达导致皮质肌动蛋白斑块和索的丢失，并且是致命的。SIW14的过表达也挽救了筛选中分离的slt2突变体的咖啡因敏感性，但这不是由于slt2磷酸化状态的改变。这些观察结果表明，内吞作用和肌动蛋白细胞骨架的组织是对营养限制的适当反应所必需的。这一假设得到了rvs161Delta、sla1Delta、sla2Delta、vrp1Delta、ypt51Delta、ypt52Delta和end3Delta突变的支持，这些突变破坏肌动蛋白细胞骨架的组织和/或减少内噬作用，其表型与wh2delta突变相似。
Saccharomyces cerevisiae whi2Delta cells are unable to halt cell division in response to nutrient limitation and are sensitive to a wide variety of stresses. A synthetic lethal screen resulted in the isolation of siw mutants that had a phenotype similar to that of whi2Delta. Among these were mutations affecting SIW14, FEN2, SLT2, and THR4. Fluid-phase endocytosis is severely reduced or abolished in whi2Delta, siw14Delta, fen2Delta, and thr4Delta mutants. Furthermore, whi2Delta and siw14Delta mutants produce large actin clumps in stationary phase similar to those seen in prk1Delta ark1Delta mutants defective in protein kinases that regulate the actin cytoskeleton. Overexpression of SIW14 in a prk1Delta strain resulted in a loss of cortical actin patches and cables and was lethal. Overexpression of SIW14 also rescued the caffeine sensitivity of the slt2 mutant isolated in the screen, but this was not due to alteration of the phosphorylation state of Slt2. These observations suggest that endocytosis and the organization of the actin cytoskeleton are required for the proper response to nutrient limitation. This hypothesis is supported by the observation that rvs161Delta, sla1Delta, sla2Delta, vrp1Delta, ypt51Delta, ypt52Delta, and end3Delta mutations, which disrupt the organization of the actin cytoskeleton and/or reduce endocytosis, have a phenotype similar to that of whi2Delta mutants.