title: Phytochrome phosphorylation modulates light signaling by influencing the protein-protein interaction.
abstract: Plant photoreceptor phytochromes are phosphoproteins, but the question as to the functional role of phytochrome phosphorylation has remained to be elucidated. We investigated the functional role of phytochrome phosphorylation in plant light signaling using a Pfr-specific phosphorylation site mutant, Ser598Ala of oat (Avena sativa) phytochrome A (phyA). The transgenic Arabidopsis thaliana (phyA-201 background) plants with this mutant phyA showed hypersensitivity to light, suggesting that phytochrome phosphorylation at Serine-598 (Ser598) in the hinge region is involved in an inhibitory mechanism. The phosphorylation at Ser598 prevented its interaction with putative signal transducers, Nucleoside Diphosphate Kinase-2 and Phytochrome-Interacting Factor-3. These results suggest that phosphorylation in the hinge region of phytochromes serves as a signal-modulating site through the protein-protein interaction between phytochrome and its putative signal transducer proteins.
authors.affiliation: Kumho Life and Environmental Science Laboratory, Gwangju 500-712, Korea.
authors.forename: Jeong-Il
authors.initials: JI
authors.lastname: Kim
authors.forename: Yu
authors.initials: Y
authors.lastname: Shen
authors.forename: Yun-Jeong
authors.initials: YJ
authors.lastname: Han
authors.forename: Joung-Eun
authors.initials: JE
authors.lastname: Park
authors.forename: Daniel
authors.initials: D
authors.lastname: Kirchenbauer
authors.forename: Moon-Soo
authors.initials: MS
authors.lastname: Soh
authors.forename: Ferenc
authors.initials: F
authors.lastname: Nagy
authors.forename: Eberhard
authors.initials: E
authors.lastname: Schäfer
authors.forename: Pill-Soon
authors.initials: PS
authors.lastname: Song
mesh_terms: D018554:Avena / Q000201:enzymology / Q000378:metabolism; D001483:Base Sequence; D017931:DNA Primers; D008027:Light; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism; D010766:Phosphorylation; D010834:Phytochrome / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D015398:Signal Transduction
chemical_list: D017931:DNA Primers; D010940:Plant Proteins; D010834:Phytochrome; C121988:nucleoside diphosphate kinase 2; D009701:Nucleoside-Diphosphate Kinase