title: A Raf-like protein kinase BHP mediates blue light-dependent stomatal opening.
abstract: Stomata in the plant epidermis open in response to blue light and affect photosynthesis and plant growth by regulating CO2uptake and transpiration. In stomatal guard cells under blue light, plasma membrane H+-ATPase is phosphorylated and activated via blue light-receptor phototropins and a signaling mediator BLUS1, and H+-ATPase activation drives stomatal opening. However, details of the signaling between phototropins and H+-ATPase remain largely unknown. In this study, through a screening of specific inhibitors for the blue light-dependent H+-ATPase phosphorylation in guard cells, we identified a Raf-like protein kinase, BLUE LIGHT-DEPENDENT H+-ATPASE PHOSPHORYLATION (BHP). Guard cells in the bhp mutant showed impairments of stomatal opening and H+-ATPase phosphorylation in response to blue light. BHP is abundantly expressed in the cytosol of guard cells and interacts with BLUS1 both in vitro and in vivo. Based on these results, BHP is a novel signaling mediator in blue light-dependent stomatal opening, likely downstream of BLUS1.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Shin-Ichiro
authors.initials: SI
authors.lastname: Inoue
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ueno
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan.|Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Kinoshita
mesh_terms: D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000378:metabolism*; D008027:Light; D010770:Phosphotransferases / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D054046:Plant Stomata / Q000201:enzymology* / Q000528:radiation effects; D015398:Signal Transduction; D048490:raf Kinases / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C000612260:BLUS1 protein, Arabidopsis; D010940:Plant Proteins; D010770:Phosphotransferases; D048490:raf Kinases