Abstract
His-to-Asp phosphorelays are involved in signal transduction in response to plant hormones and/or environmental stimuli. In general, this signal transduction system consists of three types of transducers, sensor His-kinase, histidine phosphotransmitter and response regulator(RR). Arabidopsis has 11 genes each coding His-kinase and 22 genes coding RR (ARR). Thus, a complex AHK->AHP->ARR phosphorelay network must occur in this higher plant.
ARRs can be classified into the type-A and type-B family members, and another atypical member (named ARR22). There is solid evidence for that type-A and type-B ARR family members are involved in the cytokinin signaling as negative and positive regulators, respectively. However, ARR22 is least characterized.
Here we focused on ARR22 and characterized its overexpressor. We also examined the expression profiles of ARR22 in plants and intracellular localization. Together with a microarray analysis, these results will be discussed with reference to cytokinin signal trunsduction and His-Asp phosphorelay network.
