Gopalakrishnan J, Mennella V, Blachon S, Zhai B, Smith AH, Megraw TL, Nicastro D, Gygi SP, Agard DA, Avidor-Reiss T. Sas-4 provides a scaffold for cytoplasmic complexes and tethers them in a centrosome.
Nat Commun 2011;
2:359. [PMID:
21694707 DOI:
10.1038/ncomms1367]
[Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 05/24/2011] [Indexed: 12/28/2022] Open
Abstract
Centrosomes are conserved organelles that are essential for accurate cell division and cilium formation. A centrosome consists of a pair of centrioles surrounded by a protein network of pericentriolar material (PCM) that is essential for the centrosome's function. In this study, we show that Sas-4 provides a scaffold for cytoplasmic complexes (named S-CAP), which include CNN, Asl and D-PLP, proteins that are all found in the centrosomes at the vicinity of the centriole. When Sas-4 is absent, nascent procentrioles are unstable and lack PCM, and functional centrosomes are not generated. When Sas-4 is mutated, so that it cannot form S-CAP complexes, centrosomes are present but with dramatically reduced levels of PCM. Finally, purified S-CAP complexes or recombinant Sas-4 can bind centrosomes stripped of PCM, whereas recombinant CNN or Asl cannot. In summary, PCM assembly begins in the cytosol where Sas-4 provides a scaffold for pre-assembled cytoplasmic complexes before tethering of the complexes in a centrosome.
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