title: Multiple kinases promote light-induced degradation of PIF1.
abstract: Phytochrome (phy) family of photoreceptors is a broad sensor of environmental light signals that promote photomorphogenic development of plants. Phytochrome Interacting Factors (PIFs), bHLH family of transcription factors, repress photomorphogenesis in the dark in an overlapping manner. Phytochromes interact with PIFs in response to light and induce rapid phosphorylation, poly-ubiquitylation and degradation of PIFs through the ubiquitin/26S proteasome pathway to promote photomorphogenesis. Structure-function analyses with PIF family members revealed that multiple domains are necessary for the light-induced phosphorylation and degradation of PIFs. CK2, a ubiquitious Ser/Thr kinase, phosphorylates PIF1 independent of light. In addition, PIF1 mutants deficient in CK2 phosphorylation sites are still robustly phosphorylated but not efficiently degraded in response to light. These data suggest that multiple kinases phosphorylate PIF1 to promote light-induced degradation and photomorphogenesis.
authors.affiliation: Section of Molecular Cell and Developmental Biology and The Institute for Cellular and Molecular Biology, The University of Texas at Austin, TX, USA.
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Bu
authors.forename: Ling
authors.initials: L
authors.lastname: Zhu
authors.forename: Enamul
authors.initials: E
authors.lastname: Huq
mesh_terms: D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D047390:Casein Kinase II / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008027:Light; D010766:Phosphorylation; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D059748:Proteolysis
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D047390:Casein Kinase II; D010834:Phytochrome; D010940:Plant Proteins; D017346:Protein Serine-Threonine Kinases