TY - JOUR
T1 - Identification of a regulatory subunit of protein phosphatase 1 which mediates blue light signaling for stomatal opening
AU - Takemiya, Atsushi
AU - Yamauchi, Shota
AU - Yano, Takayuki
AU - Ariyoshi, Chie
AU - Shimazaki, Ken Ichiro
N1 - Funding Information:
This work was supported by the Japanese Ministry of Education, Culture, Sports, Science, and Technology [Grant-in-Aid for Scientific Research on Innovative Areas No. 23120521 to A.T. and Grant-in-Aid for Scientific Research (S) No. 21227001 to K.S.]; the Research Foundation for Opto-Science and Technology [grant to A.T.]; the Sumitomo Foundation [grant to A.T.].
PY - 2013/1
Y1 - 2013/1
N2 - Protein phosphatase 1 (PP1) is a eukaryotic serine/threonine protein phosphatase comprised of a catalytic subunit (PP1c) and a regulatory subunit that modulates catalytic activity, subcellular localization and substrate specificity. PP1c positively regulates stomatal opening through blue light signaling between phototropins and the plasma membrane H+-ATPase in guard cells. However, the regulatory subunit functioning in this process is unknown. We identified Arabidopsis PRSL1 (PP1 regulatory subunit2-like protein1) as a regulatory subunit of PP1c. Tautomycin, a selective inhibitor of PP1c, inhibited blue light responses of stomata in the single mutants phot1 and phot2, supporting the idea that signals from phot1 and phot2 converge on PP1c. We obtained PRSL1 based on the sequence similarity to Vicia faba PRS2, a PP1c-binding protein isolated by a yeast two-hybrid screen. PRSL1 bound to Arabidopsis PP1c through its RVxF motif, a consensus PP1c-binding sequence. Arabidopsis prsl1 mutants were impaired in blue light-dependent stomatal opening, H+ pumping and phosphorylation of the H+-ATPase, but showed normal phototropin activities. PRSL1 complemented the prsl1 phenotype, but not if the protein carried a mutation in the RVxF motif, suggesting that PRSL1 functions through binding PP1c via the RVxF motif. PRSL1 did not affect the catalytic activity of Arabidopsis PP1c but it stimulated the localization of PP1c in the cytoplasm. We conclude that PRSL1 functions as a regulatory subunit of PP1 and regulates blue light signaling in stomata.
AB - Protein phosphatase 1 (PP1) is a eukaryotic serine/threonine protein phosphatase comprised of a catalytic subunit (PP1c) and a regulatory subunit that modulates catalytic activity, subcellular localization and substrate specificity. PP1c positively regulates stomatal opening through blue light signaling between phototropins and the plasma membrane H+-ATPase in guard cells. However, the regulatory subunit functioning in this process is unknown. We identified Arabidopsis PRSL1 (PP1 regulatory subunit2-like protein1) as a regulatory subunit of PP1c. Tautomycin, a selective inhibitor of PP1c, inhibited blue light responses of stomata in the single mutants phot1 and phot2, supporting the idea that signals from phot1 and phot2 converge on PP1c. We obtained PRSL1 based on the sequence similarity to Vicia faba PRS2, a PP1c-binding protein isolated by a yeast two-hybrid screen. PRSL1 bound to Arabidopsis PP1c through its RVxF motif, a consensus PP1c-binding sequence. Arabidopsis prsl1 mutants were impaired in blue light-dependent stomatal opening, H+ pumping and phosphorylation of the H+-ATPase, but showed normal phototropin activities. PRSL1 complemented the prsl1 phenotype, but not if the protein carried a mutation in the RVxF motif, suggesting that PRSL1 functions through binding PP1c via the RVxF motif. PRSL1 did not affect the catalytic activity of Arabidopsis PP1c but it stimulated the localization of PP1c in the cytoplasm. We conclude that PRSL1 functions as a regulatory subunit of PP1 and regulates blue light signaling in stomata.
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U2 - 10.1093/pcp/pcs073
DO - 10.1093/pcp/pcs073
M3 - Article
C2 - 22585556
AN - SCOPUS:84872359577
VL - 54
SP - 24
EP - 35
JO - Plant and Cell Physiology
JF - Plant and Cell Physiology
SN - 0032-0781
IS - 1
ER -