过量表达的出芽酵母蛋白激酶Ypk1磷酸化调控
Phosphorylation Regulation of Overexpressed Protein Kinase Ypk1 in Budding Yeast
黄鹏 1郄蓓蓓 1闾磊 1刘军 1杜林方 1刘科1
作者信息
- 1. 四川大学生命科学学院生物资源与生态环境教育部重点实验室 成都610064
- 折叠
摘要
出芽酵母(Saccharomyces cerevisiae)中的Ypk1与人体蛋白激酶SGK(Human serum-and glucocorticoid-inducible kinase)同源.Ypk1的504位苏氨酸残基是其激活环内的磷酸化位点,也称之为PDK1位点,而662位苏氨酸残基是位于其疏水区的PDK2位点,这两个位点的磷酸化对其激酶活性非常重要.对Ypk1过量表达后其PDKI和PDK2位点的磷酸化调控研究结果显示,Ypk1过量表达后其PDK1和PDK2位点磷酸化水平在对数生长期呈现递增趋势,至平台期趋于稳定并在7d的时序衰老过程中始终维持较高的磷酸化水平.在野生型细胞中分别过量表达Ypk1T504A和Ypk1T662A两个突变体会导致细胞对渗透压胁迫敏感性增加.而短暂渗透压胁迫处理会导致过量表达的Ypk1的PDK1和PDK2位点部分去磷酸化.研究结果表明过量表达的Ypk1的PDK1和PDK2位点磷酸化在出芽酵母时序衰老及胁迫应答过程中发挥着重要作用.图5参16
Abstract
The budding yeast protein kinase Ypkl is a homologue of mammalian protein kinase SGK (human serum-and inducible glucocorticoid-kinase).Ypkl involves in many physiological processes, including cell wall integrity, endocytosis,and sphingolipid synthesis regulation during membrane stress.The residue Thr504 is the phosphorylation site in the activation loop of Ypkl, also called PDK1 site, whereas the residue Thr662 is the phosphorylation site in the hydrophobic pocket, also called PDK2 site.These two sites are of importance to Ypkl activity.This study mainly focused on how the phosphorylation of these two sites was regulated after Ypkl overexpression.Our results showed that in exponential growth phase the phosphorylation level of PDK1 and PDK2 in overexpressed Ypkl increased gradually, whereas it became stable when cells entered stationary phase.During the 7 days of chronological aging, PDK1 and PDK2 sites of overexpressed Ypkl maintained a high phosphorylation level.Overexpression of variant Ypkl-T504A or Ypkl-T662A in BY4741 strain resulted in cells more sensitive to osmotic stress.Furthermore, transient osmotic stress treatment induced Ypkl partial dephosphorylation.This study suggested that the phosphorylation of PDK1 and PDK2 sites in Ypkl plays important regulatory roles during chronological aging and stress response.Fig 5, Ref 16
关键词
出芽酵母/Ypk1/PDK1位点/PDK2位点/磷酸化/胁迫应答/时序衰老Key words
budding yeast/Ypkl/PDK1 site/PDK2 site/phosphorylation/stress response/chronological aging引用本文复制引用
出版年
2013
NETL
NSTL
维普
万方数据