The Caenorhabditis elegans pericentriolar material components SPD-2 and SPD-5 are monomeric in the cytoplasm before incorporation into the PCM matrix.
Bottom Line: We show that SPD-2 is monomeric, and neither SPD-2 nor SPD-5 exists in complex with PLK-1.SPD-5 exists mostly as a monomer but also forms complexes with the PP2A-regulatory proteins RSA-1 and RSA-2, which are required for microtubule organization at centrosomes.These results suggest that the interactions between SPD-2, SPD-5, and PLK-1 do not result in formation of cytoplasmic complexes, but instead occur in the context of PCM assembly.
Affiliation: Max Planck Institute for Molecular Cell Biology and Genetics, 01307 Dresden, Germany.Show MeSH
Mentions: Size-exclusion chromatography revealed that SPD-2 migrated with a hydrodynamic radius (Rh) of ∼6.0 nm (Figure 2, A and B), and rate-zonal ultracentrifugation showed a peak fraction for SPD-2 with a Svedberg coefficient (Sexp) of 3.8 S (Figure 2, C and D). These values yield a calculated molecular weight of 95 kDa (monomeric molecular weight, 92 kDa) and a shape factor of 1.94 (Table 1), indicating that SPD-2 exists as an elongated monomer (Erickson et al., 2009).
Affiliation: Max Planck Institute for Molecular Cell Biology and Genetics, 01307 Dresden, Germany.