Plant histidine kinases: an emerging picture of two-component signal transduction in hormone and environmental responses.
In the Arabidopsis thaliana genome, 11 genes encode bacterial-type two-component histidine kinases. Genetic and biochemical analyses indicate that five two-component histidine kinase-like proteins (ETR1, ETR2, EIN4, ERS1, and ERS2) function as ethylene receptors. A hybrid histidine kinase, CRE1 (also known as AHK4), acts as a cytokinin receptor, and a set of response regulators may be involved in cytokinin signal transduction. In addition to CRE1, histidine kinases CKI1 and CKI2 are likely to play important roles in cytokinin signaling. A database search of the entire Arabidopsis genome sequence has identified two additional homologs of CRE1. Arabidopsis seems to employ a hybrid histidine kinase, ATHK1, as an osmosensor. Plants widely use two-component systems in the detection of, and signal transduction by, the growth regulators ethylene and cytokinin, as well as in their responses to environmental stimuli.
Urao
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Biological Resources Division, Japan International Research Center for Agricultural Science (JIRCAS), Ministry of Agriculture, Forestry and Fisheries, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Yamaguchi-Shinozaki
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Shinozaki
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K
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D000071677:Histidine Kinase; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*
D011494:Protein Kinases; D000071677:Histidine Kinase