Arabidopsis cytokinin signaling pathway.
Cytokinins are essential plant hormones that control cell division, shoot meristem initiation, leaf and root differentiation, vasculature patterning, chloroplast biogenesis, photomorphogenesis, fertility, seed development, senescence, and stress tolerance. The Arabidopsis cytokinin signal transduction pathway involves hybrid histidine protein kinases [AHK2, AHK3, and AHK4 (also known as CRE1or WOL)] as cytokinin receptors, histidine phosphotransfer proteins (AHPs), and nuclear response regulators (ARRs) that serve as transcriptional regulators. There are four major steps in the cytokinin phosphorelay: (i) AHK sensing and signaling, (ii) AHP nuclear translocation, (iii) ARR-dependent transcriptional activation, and (iv) a negative-feedback loop through cytokinin-inducible ARR gene products. Each step is executed by components encoded by multigene families. The effects of cytokinin depend on cell type, environment, and developmental stage. The response is frequently the outcome of interactions with other plant signaling pathways.
Müller
Bruno
B
Department of Molecular Biology, Massachusetts General Hospital, and Harvard Medical School, Boston, MA 02114, USA.
Sheen
Jen
J
D021581:Active Transport, Cell Nucleus; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism*; D025461:Feedback, Physiological; D018506:Gene Expression Regulation, Plant; D000071677:Histidine Kinase; D010766:Phosphorylation; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D003583:Cytokinins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase; C000605492:AHK2 protein, Arabidopsis; C000605493:AHK3 protein, Arabidopsis; C421783:WOL protein, Arabidopsis