Key points are not available for this paper at this time.
Centrosomes are highly dynamic organelles, and maintaining their stability is crucial for spindle pole integrity and bipolar spindle formation. Centrosomes consist of a pair of centrioles surrounded by the PCM. In Caenorhabditis elegans, interactions between the scaffold protein SPD-5 and kinase PLK-1 are essential for PCM formation. However, how PCM stability is established and maintained remains unclear. We address this by analyzing the function of PCMD-1, a protein mainly localizing to centrioles. We show that CDK-1 primes PCMD-1 for PLK-1 phosphorylation. Mutations in PLK-1 docking sites abolish PCMD-1 phosphorylation and SPD-5 binding in vitro and destabilize the PCM scaffold in vivo. As a result, microtubule-pulling forces cannot be relayed to centrioles, delaying their separation. Our findings reveal that PCMD-1 is critical for PCM stability and timely centriole separation during PCM disassembly. We propose that PCMD-1 initiates scaffold assembly by biasing the PCM core toward intrinsic order, acting as a seed that propagates throughout the scaffold to ensure structural integrity.
Schreiner et al. (Wed,) studied this question.