title: Phytochrome-specific type 5 phosphatase controls light signal flux by enhancing phytochrome stability and affinity for a signal transducer.
abstract: Environmental light information such as quality, intensity, and duration in red (approximately 660 nm) and far-red (approximately 730 nm) wavelengths is perceived by phytochrome photoreceptors in plants, critically influencing almost all developmental strategies from germination to flowering. Phytochromes interconvert between red light-absorbing Pr and biologically functional far-red light-absorbing Pfr forms. To ensure optimal photoresponses in plants, the flux of light signal from Pfr-phytochromes should be tightly controlled. Phytochromes are phosphorylated at specific serine residues. We found that a type 5 protein phosphatase (PAPP5) specifically dephosphorylates biologically active Pfr-phytochromes and enhances phytochrome-mediated photoresponses. Depending on the specific serine residues dephosphorylated by PAPP5, phytochrome stability and affinity for a downstream signal transducer, NDPK2, were enhanced. Thus, phytochrome photoreceptors have developed an elaborate biochemical tuning mechanism for modulating the flux of light signal, employing variable phosphorylation states controlled by phosphorylation and PAPP5-mediated dephosphorylation as a mean to control phytochrome stability and affinity for downstream transducers.
authors.affiliation: Division of Molecular and Life Sciences and Systems Bio-Dynamics Research Center, Pohang University of Science and Technology, Hyoja-dong, Pohang, Kyungbuk, 790-784, Republic of Korea.
authors.forename: Jong Sang
authors.initials: JS
authors.lastname: Ryu
authors.forename: Jeong-Il
authors.initials: JI
authors.lastname: Kim
authors.forename: Tim
authors.initials: T
authors.lastname: Kunkel
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Kim
authors.forename: Dae Shik
authors.initials: DS
authors.lastname: Cho
authors.forename: Sung Hyun
authors.initials: SH
authors.lastname: Hong
authors.forename: Seong-Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Aurora Piñas
authors.initials: AP
authors.lastname: Fernández
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kim
authors.forename: Jose M
authors.initials: JM
authors.lastname: Alonso
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Ecker
authors.forename: Ferenc
authors.initials: F
authors.lastname: Nagy
authors.forename: Pyung Ok
authors.initials: PO
authors.lastname: Lim
authors.forename: Pill-Soon
authors.initials: PS
authors.lastname: Song
authors.forename: Eberhard
authors.initials: E
authors.lastname: Schäfer
authors.forename: Hong Gil
authors.initials: HG
authors.lastname: Nam
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018554:Avena; D001665:Binding Sites / Q000502:physiology; D008027:Light; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D010775:Photic Stimulation; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D010834:Phytochrome / Q000378:metabolism* / Q000528:radiation effects; D030821:Plants, Genetically Modified; D017434:Protein Structure, Tertiary / Q000502:physiology; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology* / Q000528:radiation effects; D015854:Up-Regulation / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D010834:Phytochrome; D012694:Serine; C121988:nucleoside diphosphate kinase 2; D009701:Nucleoside-Diphosphate Kinase; C498049:PAPP5 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases