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Multivalent coiled-coil interactions enable full-scale centrosome assembly and strength
Manolo U Rios1, Małgorzata A Bagnucka1, Bryan D Ryder2
1Department of Cell Biology, Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
The Journal of Cell Biology
|March 8, 2024
Summary
Phosphorylation by PLK-1 opens the SPD-5 scaffold protein, enabling pericentriolar material (PCM) assembly. This process involves multivalent coiled-coil interactions, crucial for mitotic spindle organization and PCM strength.
Area of Science:
- Cell Biology
- Molecular Biology
- Structural Biology
Background:
- The pericentriolar material (PCM) is essential for organizing microtubules and forming the mitotic spindle.
- Understanding the molecular mechanisms governing PCM assembly and its mechanical properties is critical.
Purpose of the Study:
- To investigate the molecular interactions driving pericentriolar material (PCM) assembly.
- To elucidate the role of SPD-5 scaffold protein phosphorylation in PCM formation and mechanics.
Main Methods:
- Crosslinking mass spectrometry (XL-MS) to analyze protein multimerization.
- Structural analysis of specific protein regions and mutations.
- Investigating the impact of microtubule-mediated forces on PCM assembly.
Main Results:
- Phosphorylation of SPD-5 by PLK-1 eliminates intramolecular crosslinks, inducing a conformational opening.
- SPD-5 multimerization is mediated by interactions between dispersed coiled-coil domains.
- Mutations in SPD-5 interacting regions cause PCM assembly defects, partially rescued by reducing microtubule forces, indicating interdependence of assembly and strength.
Conclusions:
- PCM assembly and mechanical strength are interdependent processes.
- Multivalent coiled-coil interactions between SPD-5 proteins drive PCM size and strength.
- Phosphorylation-induced structural changes in SPD-5 are key to initiating PCM assembly.
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