Ferguson-Yankey Stacey R, Skrzypek Marek S, Lester Robert L, Dickson Robert C
Department of Molecular and Cellular Biochemistry, Lucille P. Markey Cancer Center, University of Kentucky College of Medicine, 800 Rose Street, Lexington, KY 40536, USA.
Yeast. 2002 May;19(7):573-86. doi: 10.1002/yea.861.
Sphingolipid long chain bases (LCBs) in Saccharomyces cerevisiae, dihydrosphingosine (DHS) and phytosphingosine (PHS) and their phosphates (DHS-P and PHS-P) are thought to play roles in heat stress. However, quantitative studies of LCBs and LCBPs have been limited by analytical methods. A new analytical procedure allowed us to measure changes in all known LCBPs and LCBs in wild-type and mutant cells during heat shock and to correlate the changes with heat stress resistance. All five molecular species of LCBPs increased rapidly but transiently when log and stationary phase cells were heat-stressed and when log-phase cells were induced for thermotolerance, suggesting that LCBPs play a role in heat stress. In support of this hypothesis, cells lacking the minor LCB kinase, Lcb5p, but not the major kinase, Lcb4p, were two-fold less resistant to killing when log-phase cells were induced for thermotolerance. Thus, LCBPs seem to play a minor role in heat-stress resistance. However, their role may be masked by LCBs, which are elevated in mutant strains, such as one lacking Lcb4p. This elevation demonstrates that one function of Lcb4p is to regulate LCB levels. Two new compounds, C(16) DHS and C(16) DHS-P, were identified, with the latter being degraded by the Dpl1p lyase. Our data provide a basis for determining how the basal and heat-induced levels of individual species of LCBs and LCBPs are governed by the Lcb4p and Lcb5p kinases, the Dpl1p lyase and the Lcb3p phosphatase.
酿酒酵母中的鞘脂长链碱（LCB），二氢鞘氨醇（DHS）和植物鞘氨醇（PHS）及其磷酸盐（DHS-P和PHS-P）被认为在热应激中发挥作用。然而，LCB和LCBP的定量研究一直受到分析方法的限制。一种新的分析程序使我们能够测量野生型和突变细胞在热休克期间所有已知LCBP和LCB的变化，并将这些变化与耐热性相关联。当对数期和稳定期细胞受到热应激时，以及对数期细胞被诱导耐热时，所有五种LCBP分子种类均迅速但短暂地增加，这表明LCBP在热应激中起作用。为支持这一假设，当对数期细胞被诱导耐热时，缺乏次要LCB激酶Lcb5p而非主要激酶Lcb4p的细胞对杀伤的抗性降低了两倍。因此，LCBP似乎在耐热性中起次要作用。然而，它们的作用可能被突变菌株（如缺乏Lcb4p的菌株）中升高的LCB所掩盖。这种升高表明Lcb4p的一个功能是调节LCB水平。鉴定出两种新化合物，C(16) DHS和C(16) DHS-P，后者被Dpl1p裂解酶降解。我们的数据为确定LCB和LCBP的各个种类的基础水平和热诱导水平如何受Lcb4p和Lcb5p激酶、Dpl1p裂解酶和Lcb3p磷酸酶调控提供了依据。
