An inositol polyphosphate 5-phosphatase functions in PHOTOTROPIN1 signaling in Arabidopis by altering cytosolic Ca2+.
Inositol polyphosphate 5-phosphatase (5PTase) is a key enzyme in the phosphatidylinositol metabolic pathway, which plays critical roles in a number of cellular processes in plants. Our previous work implicated the role of 5PTase13, which encodes a WD40-containing type II 5PTase, in hormone-mediated cotyledon vein development. Here, we show that 5PTase13 is also involved in blue light responses in Arabidopsis thaliana. Compared with that in darkness, the expression of 5PTase13 was suppressed by blue light irradiation, and disruption of the gene resulted in shortened hypocotyls and expanded cotyledons. Genetic analysis showed that 5PTase13 acted independently from CRYPTOCHROME1 and CONSTITUTIVE PHOTOMORPHOGENIC1 but interacted functionally with PHOTOTROPIN1 (PHOT1). The expression level of 5PTase13 was significantly enhanced in phot1 single or phot1 phot2 double mutants under blue light, and suppression of 5PTase13 expression rescued the elongated hypocotyls in the phot1 or phot1 phot2 mutants. Further analysis showed that the blue light-induced elevation of cytosolic Ca2+ was inhibited in the phot1 mutant but enhanced in the 5pt13 mutant, suggesting that 5PTase13 antagonizes PHOT1-mediated effects on calcium signaling under blue light.
Chen
Xu
X
Shanghai Institutes for Biological Science-University of California Berkeley Center of Molecular Life Sciences, Chinese Academy of Sciences, 20032 Shanghai, China.
Lin
Wen-Hui
WH
Wang
Yuan
Y
Luan
Sheng
S
Xue
Hong-Wei
HW
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D018548:Cotyledon / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D056931:Cryptochromes; D003600:Cytosol / Q000378:metabolism; D005420:Flavoproteins / Q000235:genetics / Q000378:metabolism; D018546:Hypocotyl / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D047468:Immunoprecipitation; D008027:Light; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D020798:Two-Hybrid System Techniques; D044767:Ubiquitin-Protein Ligases; D000099182:Phosphoinositide 5-Phosphatases
D029681:Arabidopsis Proteins; D002118:Calcium; D056931:Cryptochromes; D005420:Flavoproteins; D010750:Phosphoproteins; D010744:Phosphoric Monoester Hydrolases; D017346:Protein Serine-Threonine Kinases; D044767:Ubiquitin-Protein Ligases; D000099182:Phosphoinositide 5-Phosphatases; C538962:CRY1 protein, Arabidopsis; C423903:PHOT2 protein, Arabidopsis; C471983:AT2G32950 protein, Arabidopsis; C103646:NPH1 protein, Arabidopsis; C499855:5PTase13 protein, Arabidopsis