The Caenorhabditis elegans pericentriolar material components SPD-2 and SPD-5 are monomeric in the cytoplasm before incorporation into the PCM matrix.
Mol Biol Cell
; 25(19): 2984-92, 2014 Oct 01.
Article
in En
| MEDLINE
| ID: mdl-25103243
ABSTRACT
Centrosomes are the main microtubule-organizing centers in animal cells. Centrosomes consist of a pair of centrioles surrounded by a matrix of pericentriolar material (PCM) that assembles from cytoplasmic components. In Caenorhabditis elegans embryos, interactions between the coiled-coil proteins SPD-5 and SPD-2 and the kinase PLK-1 are critical for PCM assembly. However, it is not known whether these interactions promote the formation of cytoplasmic complexes that are added to the PCM or whether the components interact only during incorporation into the PCM matrix. Here we address this problem by using a combination of live-cell fluorescence correlation spectroscopy, mass spectrometry, and hydrodynamic techniques to investigate the native state of PCM components in the cytoplasm. 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Caenorhabditis elegans
/
Centrosome
/
Cell Cycle Proteins
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Cytoplasm
/
Caenorhabditis elegans Proteins
Limits:
Animals
Language:
En
Journal:
Mol Biol Cell
Journal subject:
BIOLOGIA MOLECULAR
Year:
2014
Document type:
Article
Affiliation country:
Germany