高等植物中蛋白磷酸酶2C的结构与功能

蛋白质磷酸化／去磷酸化是生物信号级联传递的重要方式之一，主要通过生化性质互为对立的蛋白激酶和蛋白磷酸酶实现。蛋白磷酸酶2C(PP2C)是蛋白磷酸酶的一个分支，其生化性质、蛋白质组成与结构都和其他磷酸酶显著不同，但都在生物信号传递中扮演重要角色。高等植物中PP2C广泛参与脱落酸(ABA)的各种信号途径，包括ABA诱导的种子萌发／休眠、保卫细胞及离子通道调控和气孔关闭、逆境胁迫等。PP2C也多样地参与植物创伤反应、生长发育以及抗病性等各个途径。作为大多数信号途径的负调控因子，PP2C能直接与激酶结合，与其他调控蛋白结合，以及直接与DNA结合调控相关基因的表达。

The Structure and Function of Protein Phosphatase 2Cs in Higher Plants

Protein phosphorylation and dephosphorylation, which are mainly done by protein kinases andphosphatases, two kinds of enzymes possessing converse functions, are most important aspects of signal transduc-tion pathways in all kinds of organisms. Protein phosphatase 2Cs (PP2Cs) are a subfamily of protein phosphatasesand their biochemical properties and protein structures distinguish themselves from any other subgroups. PlantPP2Cs have been demonstrated to play important roles in abscisic acid (ABA)-activated multiple signal transductions,such as ABA-induced seed dormancy/germination, guard cell closure, ion tunnel regulation and stress acclimation.Meanwhile, plant PP2Cs have also been shown to be involved in signaling in wound response, development andpathogen resistance. As negative regulatory factors of many signaling events, PP2Cs can interact with kinases, otherregulatory proteins, or directly combine with DNA to control expression of corresponding genes.