Phosphorylation remodels the mitotic centrosome matrix to generate bipartite γ-tubulin complex docking sites - PubMed
3 hours ago
- #phosphorylation
- #mitotic centrosome
- #microtubule nucleation
- Phosphorylation at centrosomes during mitotic entry remodels matrix proteins like CDK5RAP2 to create docking sites for γ-tubulin complexes (γTuCs), which nucleate microtubules for spindle assembly.
- Using C. elegans SPD-5 as a model, two regions (PRGB1 and PRGB2) are identified, each sufficient for PLK1 phosphorylation-regulated γTuC binding, with defined key phosphosites and mechanisms of autoinhibition.
- PRGB2 is dimeric and requires γTuCs containing MZT-1 for binding, whereas PRGB1 is monomeric and MZT-1-independent; phosphorylation induces a conformational change enabling MZT-1-dependent PRGB2 engagement, relieving PRGB1 inhibition.
- This multistep mechanism ensures robust spindle assembly by spatially and temporally restricting microtubule nucleation.