Regulation of the Saccharomyces cerevisiae Slt2 kinase pathway by the stress-inducible Sdp1 dual specificity phosphatase
Regulation of the Saccharomyces cerevisiae Slt2 kinase pathway by the stress-inducible Sdp1 dual specificity phosphatase
复制标题
DOI：
10.1074/jbc.m202557200
复制
发表时间：
2002-06-14
影响因子：
4.8
通讯作者：
Thiele, DJ
中科院分区：
文献类型：
--
作者：
Hahn, JS;Thiele, DJ
Slt2/Mpk1丝裂原活化蛋白激酶（MAPK）细胞完整性通路参与酿酒酵母营养生长和交配过程中细胞形状和完整性的维持。Slt2通过苏氨酸和酪氨酸残基的双重磷酸化来激活，以响应干扰细胞完整性的几种环境胁迫。Slt2的负调控是通过两种蛋白酪氨酸磷酸酶Ptp2和Ptp3以及一种双特异性磷酸酶Msg5去磷酸化来实现的。在这项研究中，我们提供了遗传和生化证据，证明胁迫诱导的双特异性磷酸酶Sdp1通过直接去磷酸化负调控Slt2。由于Slt2 MAPK激酶的组成型活性突变体Mkk1（p386）的过表达，SDP1的缺失加剧了生长缺陷，而SDP1的过表达抑制了Mkk1（p386）引起的致病性。超表达。与野生型相比，热休克诱导的Slt2磷酸化水平在sdp1Delta菌株中升高，热休克激活的磷酸化-Slt2在体外被重组Sdp1去磷酸化。在正常生长条件下，Sdp1-GFP融合蛋白定位于细胞核和细胞质中。然而，在热休克后，Sdp1-GFP蛋白在整个细胞中易位到点状点。SDP1转录在多种胁迫条件下以msn2 /4依赖性方式诱导，但不依赖于由Slt2激活的下游靶标Rlm1转录因子。高渗透压诱导SLT2依赖于Rlm1转录因子和Hog1激酶，表明SLT2和Hog1 MAPK通路之间存在交叉。这些研究表明Slt2活性和基因表达的调控与其他应激信号通路协调。
The Slt2/Mpk1 mitogen-activated protein kinase (MAPK) cell integrity pathway is involved in maintenance of cell shape and integrity during vegetative growth and mating in Saccharomyces cerevisiae. Slt2 is activated by dual phosphorylation of a threonine and tyrosine residue in response to several environmental stresses that perturb cell integrity. Negative regulation of Slt2 is achieved via dephosphorylation by two protein-tyrosine phosphatases, Ptp2 and Ptp3, and a dual specificity phosphatase, Msg5. In this study, we provide genetic and biochemical evidence that the stress-inducible dual specificity phosphatase, Sdp1, negatively regulates Slt2 by direct dephosphorylation. Deletion of SDP1 exacerbated growth defects due to overexpression of Mkk1(p386), a constitutively active mutant of Slt2 MAPK kinase, whereas overexpression of Sdp1 suppressed lethality caused by Mkk1(p386). overexpression. The heat shock-induced phosphorylation level of Slt2 was elevated in an sdp1Delta strain compared with that of the wild type, and heat shock-activated phospho-Slt2 was dephosphorylated by recombinant Sdp1 in vitro. Under normal growth conditions, an Sdp1-GFP fusion protein was localized to both the nucleus and cytoplasm. However, the Sdp1-GFP protein translocated to punctate spots throughout the cell after heat shock. SDP1 transcription was induced by several stress conditions in an Msn2/4-dependent manner but independent of the Rlm1 transcription factor, a downstream target activated by Slt2. Induction of SLT2 by high osmolarity was dependent on Rlm1 transcription factor and Hog1 kinase, suggesting cross-talk between Slt2 and Hog1 MAPK pathways. These studies demonstrate regulation of Slt2 activity and gene expression in coordination with other stress signaling pathways.