Volume 4 Supplement 1

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

Open Access

Prostaglandin-D2 synthase localises to centrioles and primary cilium, and interacts with TOPORS, implicated in retinal ciliopathy

  • B Czub1,
  • A Shah1,
  • P Kruczek1,
  • G Alfano1,
  • C Chakarova1 and
  • S Bhattacharya1
Cilia20154(Suppl 1):P15

DOI: 10.1186/2046-2530-4-S1-P15

Published: 13 July 2015

Objective

Prostaglandin-D2 synthase (PTGDS; MIM#176803) is a novel protein-partner of TOPORS (TOPORS; MIM#609507), a ubiquitously expressed nuclear and ciliary protein, implicated in retinitis pigmentosa. This study investigated the localisation of PTGDS and its potential mechanism-of-association with TOPORS.

Methods

Yeast two-hybrid screens, using TOPORS as bait, were performed against human retinal cDNA libraries. Validation and interaction-characterisation were performed in yeast, and by co-immunoprecipitation (co-IP) from HeLa cell extracts. Co-localisation studies were performed in hTERT-RPE1 cell line, and in murine retina cryo-sections. PTGDS expression was validated by RT-PCR.

Results

Co-IP demonstrated PTGDS was found in endogenous protein complexes with TOPORS, whereas in yeast PTGDS interacted most strongly with TOPORS' residues 1-380, comprising the RING-domain conferring its E3-ubiquitin-ligase activity. PTGDS co-localised with TOPORS, and centriolar markers in dividing cells, and was observed at basal body and along ciliary axoneme in ciliated cells. In mouse retina PTGDS was observed in several cell layers, partly overlapping with TOPORS in the photoreceptor layer. In human retina, RT-PCR studies demonstrated expression of several PTGDS isoforms.

Conclusion

PTGDS, a novel component of the primary cilium, could be involved in centriolar-ciliary homeostasis. This putative role of prostaglandin synthases, is additionally supported by independent findings on the role of prostaglandin-E2 in ciliogenesis. Results suggest TOPORS could regulate PTGDS levels at the cilium by marking it for degradation by the ubiquitin-proteasome system, providing a basis for understanding the retinal ciliopathy associated with TOPORS mutations.

Authors’ Affiliations

(1)
Institute of Ophthalmology, University College London

Copyright

© Czub 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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