Regulated vacuole fusion and fission in Schizosaccharomyces pombe:: an osmotic response dependent on MAP kinases
Regulated vacuole fusion and fission in Schizosaccharomyces pombe:: an osmotic response dependent on MAP kinases
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DOI：
10.1016/s0960-9822(98)00060-8
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发表时间：
1998-01-29
期刊：
影响因子：
9.2
通讯作者：
Armstrong, J
中科院分区：
文献类型：
--
作者：
Bone, N;Millar, JBA;Armstrong, J
背景资料：芽殖酵母酿酒酵母（Saccharomyces cerevisiae）使用两个促分裂原活化蛋白（MAP）激酶级联，即Hog 1 p和Mpk 1 p通路，分别对高渗和低渗应激进行信号响应。哺乳动物细胞和裂殖酵母裂殖酵母具有Hog 1 p的功能同源物- p38/RK/CSBP和Sty 1-与Hog 1 p不同，它们也介导其他反应。我们调查了S.粟酒裂殖酵母MAP激酶信号通路的一个新的描述响应渗透胁迫-液泡融合和分裂。当粟酒裂殖酵母被放入水中时，它的液泡迅速融合成更大的结构，包围着更大比例的细胞体积。在某些条件下，它的液泡可以缓慢地响应盐的碎片。裂变需要Sty 1途径，也需要Pmk 1，S.酿酒酵母Mpk 1 p.融合需要Pmk 1，Ypt 7-参与S.酿酒酵母空泡融合-和Sty 1途径的一部分，虽然Sty 1磷酸化是不受低渗conditions.Conclusions：空泡融合和裂变似乎是稳态机制，恢复浓度的胞质溶胶。与高等真核生物中的刺激分泌一样，胞膜融合是响应于外部刺激的快速且特异的膜融合过程。Sty 1途径除了在响应高渗应激中发挥作用外，还需要在基础水平上表达响应低渗应激所需的因子--这种机制可能允许细胞使用共同途径进行不同的反应。(C)当前生物有限公司
Background: The budding yeast Saccharomyces cerevisiae uses two mitogen-activated protein (MAP) kinase cascades, the Hog1p and the Mpk1p pathways, to signal responses to hypertonic and hypotonic stress, respectively. Mammalian cells and the fission yeast Schizosaccharomyces pombe have functional homologues of Hog1p - p38/RK/CSBP and Sty1 - which, unlike Hog1p, also mediate other responses. We have investigated the involvement of S. pombe MAP kinase pathways in signalling a newly described response to osmotic stress - that of vacuole fusion and fission.Results: When S. pombe is placed into water, its vacuoles rapidly fuse into larger structures enclosing a greater proportion of the cell's volume. Under some conditions, its vacuoles can slowly fragment in response to salt. Fission requires the Sty1 pathway and also Pmk1, the homologue of S. cerevisiae Mpk1p. Fusion requires Pmk1, Ypt7 - the homologue of a protein involved in S. cerevisiae vacuole fusion - and part of the Sty1 pathway, although Sty1 phosphorylation is unaffected by hypotonic conditions.Conclusions: Vacuole fusion and fission appear to be homeostatic mechanisms that restore the concentration of the cytosol. Vacuole fusion, like stimulated secretion in higher eukaryotes, is a rapid and specific process of membrane fusion in response to an external stimulus. The Sty1 pathway, in addition to its role in responding to hypertonic stress, is required at a basal level for the expression of factors required to respond to hypotonic stress - a mechanism that may allow the cell to use a common pathway for different responses. (C) Current Biology Ltd.