Phytochrome phosphorylation modulates light signaling by influencing the protein-protein interaction.
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.
Kim
Jeong-Il
JI
Kumho Life and Environmental Science Laboratory, Gwangju 500-712, Korea.
Shen
Yu
Y
Han
Yun-Jeong
YJ
Park
Joung-Eun
JE
Kirchenbauer
Daniel
D
Soh
Moon-Soo
MS
Nagy
Ferenc
F
Schäfer
Eberhard
E
Song
Pill-Soon
PS
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
D017931:DNA Primers; D010940:Plant Proteins; D010834:Phytochrome; C121988:nucleoside diphosphate kinase 2; D009701:Nucleoside-Diphosphate Kinase