title: Regulation of a cyclin-CDK-CDK inhibitor complex by inositol pyrophosphates.
abstract: In budding yeast, phosphate starvation triggers inhibition of the Pho80-Pho85 cyclin-cyclin-dependent kinase (CDK) complex by the CDK inhibitor Pho81, leading to expression of genes involved in nutrient homeostasis. We isolated myo-d-inositol heptakisphosphate (IP7) as a cellular component that stimulates Pho81-dependent inhibition of Pho80-Pho85. IP7 is necessary for Pho81-dependent inhibition of Pho80-Pho85 in vitro. Moreover, intracellular concentrations of IP7 increased upon phosphate starvation, and yeast mutants defective in IP7 production failed to inhibit Pho80-Pho85 in response to phosphate starvation. These observations reveal regulation of a cyclin-CDK complex by a metabolite and suggest that a complex metabolic network mediates signaling of phosphate availability.
authors.affiliation: Howard Hughes Medical Institute, Faculty of Arts and Sciences Center for Systems Biology, Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA.
authors.forename: Young-Sam
authors.initials: YS
authors.lastname: Lee
authors.forename: Sashidhar
authors.initials: S
authors.lastname: Mulugu
authors.forename: John D
authors.initials: JD
authors.lastname: York
authors.forename: Erin K
authors.initials: EK
authors.lastname: O'Shea
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016213:Cyclins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism*; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D016213:Cyclins; D004268:DNA-Binding Proteins; D007295:Inositol Phosphates; C060292:PHO4 protein, S cerevisiae; C066824:PHO80 protein, S cerevisiae; C081227:PHO81 protein, S cerevisiae; D011994:Recombinant Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C402123:inositol heptakisphosphate; D018844:Cyclin-Dependent Kinases; C058605:PHO85 protein, S cerevisiae; D017856:Phosphotransferases (Phosphate Group Acceptor); C098863:KCS1 protein, S cerevisiae; C099438:inositol hexakisphosphate kinase