The centrosome organizes microtubule arrays within animal cells and comprises two centrioles surrounded by an amorphous protein mass called the pericentriolar material (PCM). Despite the importance of centrosomes as microtubule-organizing centers, the mechanism and regulation of PCM assembly are not well understood. In Caenorhabditis elegans, PCM assembly requires the coiled-coil protein SPD-5. We found that recombinant SPD-5 could polymerize to form micrometer-sized porous networks in vitro. Network assembly was accelerated by two conserved regulators that control PCM assembly in vivo, Polo-like kinase-1 and SPD-2/Cep192. Only the assembled SPD-5 networks, and not unassembled SPD-5 protein, functioned as a scaffold for other PCM proteins. Thus, PCM size and binding capacity emerge from the regulated polymerization of one coiled-coil protein to form a porous network.
Science, 2015, Vol 348, Issue 6236, p. 808-812
Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Cycle Proteins; Centrosome; Metabolic Networks and Pathways; Phosphorylation; Polymerization; Protein Binding; Protein Structure, Tertiary; Protein-Serine-Threonine Kinases; Proto-Oncogene Proteins; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't