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Structural analysis of the regulation of the DYNLL/LC8 binding to Nek9 by phosphorylation

Pablo Gallego1, Adrian Velazquez-Campoy, Laura Regué

  • 1Structural Biology Unit, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.

The Journal of Biological Chemistry
|March 14, 2013
PubMed

Insights

Phosphorylation of Nek9 protein on Ser(944) disrupts its binding to dynein light chain 8 (LC8). This novel regulatory mechanism impacts cell division signaling and protein complex formation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Structural Biology

Background:

  • The NIMA family kinases (Nek9, Nek6, Nek7) regulate mitotic spindle organization.
  • Dynein light chain 8 (LC8) acts as a dimerization hub, binding to various protein partners.
  • LC8 binding to Nek9 is critical for the Nek/Nek6/7 signaling module.

Purpose of the Study:

  • To elucidate the structural basis for LC8 binding to Nek9.
  • To investigate the regulatory role of Nek9 phosphorylation on LC8 interaction.
  • To understand the impact of this regulation on cell signaling.

Main Methods:

  • X-ray crystallography of LC8 with Nek9 peptides (phosphorylated and unphosphorylated).
  • Biophysical experiments to quantify binding affinities.
  • Structural analysis of protein-protein interactions.

Main Results:

  • Two crystal structures reveal LC8 bound to Nek9 peptides.
  • Phosphorylation of Nek9 at Ser(944) significantly reduces its binding affinity to LC8.
  • Structural and biophysical data explain this diminished interaction.

Conclusions:

  • A novel phosphorylation-dependent mechanism regulates Nek9-LC8 complex formation.
  • This regulation impacts signal transduction in the Nek/Nek6/7 pathway.
  • Findings provide insights into LC8's role as a versatile protein interaction hub.

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