title: Structural modulation of phosducin by phosphorylation and 14-3-3 protein binding.
abstract: Phosducin (Pdc), a highly conserved phosphoprotein, plays an important role in the regulation of G protein signaling, transcriptional control, and modulation of blood pressure. Pdc is negatively regulated by phosphorylation followed by binding to the 14-3-3 protein, whose role is still unclear. To gain insight into the role of 14-3-3 in the regulation of Pdc function, we studied structural changes of Pdc induced by phosphorylation and 14-3-3 protein binding using time-resolved fluorescence spectroscopy. Our data show that the phosphorylation of the N-terminal domain of Pdc at Ser-54 and Ser-73 affects the structure of the whole Pdc molecule. Complex formation with 14-3-3 reduces the flexibility of both the N- and C-terminal domains of phosphorylated Pdc, as determined by time-resolved tryptophan and dansyl fluorescence. Therefore, our data suggest that phosphorylated Pdc undergoes a conformational change when binding to 14-3-3. These changes involve the G(t)βγ binding surface within the N-terminal domain of Pdc, and thus could explain the inhibitory effect of 14-3-3 on Pdc function.
authors.affiliation: Department of Physical and Macromolecular Chemistry, Charles University in Prague, Prague, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Rezabkova
authors.forename: Miroslava
authors.initials: M
authors.lastname: Kacirova
authors.forename: Miroslav
authors.initials: M
authors.lastname: Sulc
authors.forename: Petr
authors.initials: P
authors.lastname: Herman
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Vecer
authors.forename: Miroslav
authors.initials: M
authors.lastname: Stepanek
authors.forename: Veronika
authors.initials: V
authors.lastname: Obsilova
authors.forename: Tomas
authors.initials: T
authors.lastname: Obsil
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D005136:Eye Proteins / Q000737:chemistry* / Q000378:metabolism; D020555:GTP-Binding Protein Regulators / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010713:Phosphatidylcholines; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D012694:Serine / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D014364:Tryptophan
chemical_list: C496906:1-myristoyl-2-(12-((5-dimethylamino-1-naphthalenesulfonyl)amino)dodecanoyl)-sn-glycero-3-phosphocholine; D048948:14-3-3 Proteins; D005136:Eye Proteins; D020555:GTP-Binding Protein Regulators; D010713:Phosphatidylcholines; D010750:Phosphoproteins; C572235:YWHAZ protein, human; C065631:phosducin; D012694:Serine; D014364:Tryptophan