PLK4 Homodimerization is Required for CEP152 Centrosome Localization and Spindle Organization

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Biology

Background:

• Polo-Like Kinase 4 (PLK4) is a centrosome-specific kinase.
• PLK4 homodimerizes via its cryptic polo-box (CPB) region, leading to autophosphorylation and degradation.
• The CPB region also mediates interactions with centrosome recruiters CEP152 and CEP192.

Purpose of the Study:

• To investigate the role of PLK4 homodimerization in the CEP192-CEP152 network.
• To characterize a cancer-associated PLK4 variant disrupting CPB-mediated interactions.
• To understand the functional consequences of impaired PLK4 homodimerization on centrosome integrity and cell viability.

Main Methods:

• Identification and characterization of a truncated PLK4 variant.
• Analysis of PLK4 homodimerization and interaction with CEP152/CEP192 using the variant.
• Assessment of CEP152 and pericentrin localization at centrosomes during S-phase.
• Evaluation of spindle organization and cell viability during M-phase.

Main Results:

• A cancer PLK4 variant truncates the protein, abolishing homodimerization and interaction with CEP152/CEP192.
• PLK4 homodimerization is essential for maintaining CEP152 levels at centrosomes during S-phase.
• Expression of the PLK4 homodimerization mutant leads to reduced CEP152 and pericentrin levels.
• Impaired PLK4 homodimerization results in unfocused spindles and decreased cell viability.

Conclusions:

• PLK4 homodimerization and CEP152 recruitment exhibit a cross-dependency for proper centrosome function.
• Disruption of PLK4 homodimerization compromises centrosome integrity and contributes to cancer-associated defects.
• This highlights a critical regulatory mechanism at the centrosome that is altered in cancer.