Structured illumination of the interface between centriole and peri-centriolar material

Area of Science:

• Cell Biology
• Centrosome Biology
• Microscopy

Background:

• Centrosome size increases during mitosis, but the role of centrioles in organizing pericentriolar material (PCM) remains unclear.
• Centrioles are key structures within centrosomes, influencing their overall function and organization.

Purpose of the Study:

• To elucidate the spatial organization of PCM proteins around centrioles during the cell cycle.
• To understand the recruitment dynamics of PCM components during mitotic entry and meiosis.

Main Methods:

• Structured illumination microscopy in Drosophila.
• Analysis of protein localization and recruitment dynamics in relation to centrioles.

Main Results:

• Interphase centrioles exhibit two distinct layers of associated PCM proteins: an inner layer (microtubules, Sas-4, Spd-2, Polo) and an outer layer (Dplp, Asl, Plk4).
• Centrosomin (Cnn) and γ-tubulin associate with the outer layer in G2 cells and are recruited to PCM clouds upon mitotic entry, dependent on Polo activity.
• Cnn is crucial for Spd-2 expansion into PCM and can contribute independently, while spermatocyte centrioles show distinct protein segregation in proximal regions before meiosis.

Conclusions:

• Centriole structure dictates the initial spatial organization of PCM proteins.
• Protein recruitment and maturation into PCM clouds involve specific kinases and organizational factors like Cnn.
• Spatial compartmentalization of proteins on centrioles is dynamic and changes with cell cycle progression, particularly preceding meiosis.