Structural modulation of phosducin by phosphorylation and 14-3-3 protein binding

Biophys J. 2012 Nov 7;103(9):1960-9. doi: 10.1016/j.bpj.2012.09.021.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins / metabolism*
  • Amino Acid Sequence
  • Animals
  • Eye Proteins / chemistry*
  • Eye Proteins / metabolism
  • GTP-Binding Protein Regulators / chemistry*
  • GTP-Binding Protein Regulators / metabolism
  • Humans
  • Molecular Sequence Data
  • Phosphatidylcholines
  • Phosphoproteins / chemistry*
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Structure, Tertiary
  • Rats
  • Serine / metabolism
  • Spectrometry, Fluorescence
  • Tryptophan


  • 1-myristoyl-2-(12-((5-dimethylamino-1-naphthalenesulfonyl)amino)dodecanoyl)-sn-glycero-3-phosphocholine
  • 14-3-3 Proteins
  • Eye Proteins
  • GTP-Binding Protein Regulators
  • Phosphatidylcholines
  • Phosphoproteins
  • YWHAZ protein, human
  • phosducin
  • Serine
  • Tryptophan