Suzuki T, Miwa K, Ishikawa K, Yamada H, Aiba H, Mizuno T
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan.
Plant Cell Physiol. 2001 Feb;42(2):107-13. doi: 10.1093/pcp/pce037.
His-to-Asp (His-->Asp) phosphorelay mechanisms are presumably involved in propagation of certain environmental stimuli, including phytohormones, in Arabidopsis thaliana. In addition to the previously characterized His-kinases, namely, the ETR1 family of ethylene receptors, CKI1 cytokinin-sensor, and ATHK1 osomo-sensor, this higher plant has three more His-kinases (named AHK2, AHK3, and AHK4). By employing the well-known His-->Asp phosphorelay systems in both the fission yeast and Escherichia coli, evidence is presented showing that the AHK4 His-kinase has an ability to serve as a cytokinin-responsive environmental sensor. Taking advantage of this AHK4-dependent His-->Asp phosphorelay system in E. coli, a phosphorelay interaction between the Arabidopsis His-kinase and histidine-containing phosphotransmitters (AHPs) was also demonstrated for the first time.
在拟南芥中，组氨酸到天冬氨酸（His→Asp）的磷酸化传递机制可能参与包括植物激素在内的某些环境刺激的传导。除了先前已鉴定的组氨酸激酶，即乙烯受体的ETR1家族、细胞分裂素传感器CKI1和渗透传感器ATHK1外，这种高等植物还有另外三种组氨酸激酶（命名为AHK2、AHK3和AHK4）。通过利用裂殖酵母和大肠杆菌中著名的His→Asp磷酸化传递系统，有证据表明AHK4组氨酸激酶能够作为细胞分裂素响应性环境传感器。利用大肠杆菌中这种依赖AHK4的His→Asp磷酸化传递系统，还首次证明了拟南芥组氨酸激酶与含组氨酸的磷酸传递体（AHPs）之间的磷酸化传递相互作用。
