植物PP2C蛋白磷酸酶ABA信号转导及逆境胁迫调控机制研究进展

蛋白磷酸酶(protein phosphatase,PP)是蛋白质可逆磷酸化调节机制中的关键酶,而PP2C磷酸酶是一类丝氨酸/苏氨酸残基蛋白磷酸酶,是高等植物中最大的蛋白磷酸酶家族,包含76个家族成员,广泛存在于生物体中。迄今为止,在植物体内已经发现了4种PP2C蛋白磷酸酶。蛋白激酶和蛋白磷酸酶协同催化蛋白质可逆磷酸化,在植物体内信号转导和生理代谢中起着重要的调节作用,蛋白质的磷酸化几乎存在于所有的信号转导途径中。大量研究表明,PP2Cs参与多条信号转导途径,包括PP2C参与ABA调控,对干旱、低温、高盐等逆境胁迫的响应,参与植物创伤和种子休眠或萌发等信号途径,其调控机制不同,但酶催化活性都依赖于Mg2+或Mn2+的浓度。植物PP2C蛋白的C端催化结构域高度保守,而N端功能各异。文中还综述了高等植物PP2C的分类、结构、ABA受体与PP2Cs蛋白互作、PP2C基因参与ABA信号途径以及其他逆境信号转导途径的研究进展。

Research progress of plant PP2C-type protein phosphatase in ABA signal transduction and adversity stress regulation mechanism

Protein phosphatase is the most important and pivotal enzymes in reversible protein phosphorylation regulating mechanisms. While the PP2C phosphatase is a kind of serine/ threonine residues of protein phosphatase, is the largest protein phosphatase family in higher plants, there are 76 family members, widely exists in living organisms. So far, four kinds of PP2C protein phosphatases have been found in plants. Protein kinase and protein phosphatase catalyzed reversible protein phosphorylation, play an important role in plant signal transduction and physiological metabolism, protein phosphorylation exist in almost the signal transduction pathway. Numerous academic studies have shown that plant PP2Cs are involved in multiple signal transduction pathways including PP2C involved in ABA signaling pathway, the response to drought, low temperature, salt stress, participated in the plant wound and seed dormancy or germination signal pathway, and exist the different regulation mechanism and the enzyme catalytic activity were dependent on the concentrations of Mg²⁺ or Mn²⁺. In plant PP2Cs protein C-terminal, there are a highly conserved catalytic domains, as well as in their N-terminal, their function are different. The review would provide a brief overview of classification, structure of PP2Cs, the interaction between ABA receptor and PP2Cs protein, the recent progresses about their roles in ABA and other stress signal transduction pathway in higher plant.