Volume 4 Supplement 1

Proceedings of the Second International Cilia in Development and Disease Scientific Conference (2014)

Open Access

CSPP-L and EB3 localize to centriolar satellites and are required for satellite-dependent recruitment of ciliopathy proteins to the centrosome

  • J Sternemalm1,
  • S Geimer2,
  • EK Aarnes1,
  • KM Frikstad1,
  • T Stokke1,
  • LB Pedersen3 and
  • S Patzke1
Cilia20154(Suppl 1):P76

DOI: 10.1186/2046-2530-4-S1-P76

Published: 13 July 2015

Objective

Centrosome/Spindle Pole associated Protein 1 (CSPP1, JBTS21) mutations cause Joubert syndrome (JBTS) and JBTS-related ciliopathies. The large protein isoform CSPP-L is a ciliary protein required for ciliogenesis and stabilization of the ciliopathy protein RPGRIP1L (NPHP8/JBTS7/MKS5/FTM) at the ciliary transition zone (TZ). However, RPGRIP1L is dispensable for ciliogenesis and the mechanism by which CSPP-L promotes ciliogenesis is unclear.

Methods

We applied immunogold electron, immunofluorescence and fluorescence live cell microscopy to determine localization of CSPP-L at high spatial and temporal resolution. We elucidated the functional interplay of CSPP-L with centriolar satellites in hTERT-RPE1 and HeLa cells using biochemical analysis of CSPP-L complexes, siRNA modulated gene expression and quantitative immunofluoresecence microscopy.

Results

We show that CSPP-L localizes to centriolar satellites, in addition to axonemal microtubule (MT) plus ends and the TZ, and that the MT plus end-tracking protein EB3 also localizes to satellites. CSPP-L complexed with the known satellite component PCM1 and GFP-CSPP-L showed satellite-like dynamics. Importantly, CSPP-L depletion decreased formation of PCM1, CEP290 and EB3-comprising satellites, whereas depletion or inactivation of EB3 impaired centrosomal localization of CSPP-L.

Conclusion

Our results identify a new link between MT plus ends and centriolar satellites, and suggest that CSPP-L contributes to ciliogenesis by promoting EB3- and dynein-dependent recruitment of satellite components to the centrosome.

Authors’ Affiliations

(1)
Institute for Cancer Research, Dept Radiation Biology, OUH - Norwegian Radium Hospital
(2)
Cell Biology / Electron Microscopy, University of Bayreuth
(3)
Department of Biology, University of Copenhagen

Copyright

© Sternemalm et al. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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