Activation of the cell integrity pathway is channelled through diverse signalling elements in fission yeast
Activation of the cell integrity pathway is channelled through diverse signalling elements in fission yeast
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DOI：
10.1016/j.cellsig.2007.12.017
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发表时间：
2008-04-01
影响因子：
4.8
通讯作者：
Cansado, Jose
中科院分区：
文献类型：
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作者：
Barba, Gregorio;Soto, Teresa;Cansado, Jose
在裂殖酵母中，MAPK Pmk1p是参与维持细胞完整性和其他功能的级联反应的中心元件。Pmk1p在多种应激情况下被激活，在细胞分离过程中也是如此。GTP酶Rho2p通过与MAPKKK Mkh1p直接相互作用，作用于蛋白激酶C同系物Pck 2p的上游，激活Pmk1信号通路。在这项工作中，我们分析了Rho2p和Pck 2p在通过细胞完整性途径传递各种胁迫信号中的功能意义。结果表明，Pmk1p的基础活性可以被不受Rho2p和/或Pck 2p控制的其他机制正向调节。出乎意料的是，另一种蛋白激酶C同源物Pck 1p通过一种未知的机制负向调节Pmk1p的基础活性。此外，不同的元件似乎调节应激诱导的Pmk1p的激活，这取决于触发刺激的性质。高或低渗应激诱导的Pmk1p激活是通过Rho2p-Pck 2p传导的，而其他应激源，如葡萄糖缺乏或细胞壁障碍，除了Rho2p-Pck 2p外，还通过其他途径进行传导。相反，在细胞分离过程中或用过氧化氢处理后观察到的Pmk1p激活不涉及Rho2p-Pck 2p。最后，Pock2p功能对于维持Pmk1p的基础活性至关重要，该基础活性允许Pmk1p在热应激诱导下激活。这些数据表明，在分裂酵母中存在一个复杂的信号网络，调节Pmk1p的激活，以响应各种压力。(C)2008 Elsevier Inc.保留所有权利。
MAPK Pmk1p is the central element of a cascade involved in the maintenance of cell integrity and other functions in Schizosaccharomyces pombe. Pmk1p becomes activated by multiple stressing situations and also during cell separation. GTPase Rho2p acts upstream of the protein kinase C homolog Pck2p to activate the Pmk1 signalling pathway through direct interaction with MAPKKK Mkh1p. In this work we analyzed the functional significance of both Rho2p and Pck2p in the transduction of various stress signals by the cell integrity pathway. The results indicate that basal Pmk1p activity can be positively regulated by alternative mechanisms which are independent on the control by Rho2p and/or Pck2p. Unexpectedly, Pck1p, another protein kinase C homolog, negatively modulates Pmk1p basal activity by an unknown mechanism. Moreover, different elements appear to regulate the stress-induced activation of Pmk1p depending on the nature of the triggering stimuli. Whereas Pmk1p activation induced by hyper- or hypotonic stresses is channeled through Rho2p-Pck2p, other stressors, like glucose deprivation or cell wall disturbance, are transduced via other pathways in addition to that of Rho2p-Pck2p. On the contrary, Pmk1p activation observed during cell separation or after treatment with hydrogen peroxide does not involve Rho2p-Pck2p. Finally, Pck2p function is critical to maintain a Pmk1p basal activity that allows Pmk1p activation induced by heat stress. These data demonstrate the existence of a complex signalling network modulating Pmk1p activation in response to a variety of stresses in fission yeast. (C) 2008 Elsevier Inc. All rights reserved.