Trypanosome flagellum transition zone proteome reveals compartmentalisation and differential dynamics of ciliopathy complexes

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Poster

136

Trypanosome flagellum transition zone proteome reveals compartmentalisation and differential dynamics of ciliopathy complexes

Authors

S Dean²; F Moreira-Leite²; V Varga¹; K Gull²;
¹ Institute of Molecular Genetics, Academy of Sciences of the Czech Republic; ² Sir William Dunn School of Pathology, University of Oxford

Discussion

The biology of the trypanosome flagellum provides opportunities for insights into trypanosome pathology and can be generalised to other eukaryotic flagella.

The flagellum transition zone (TZ) is positioned between the distal end of the basal bodies and the proximal end of the 9+2 axoneme. It is increasingly recognised as having critical roles in flagellum growth and function, acting as a “gate” that controls the composition of the flagellum. The importance of the TZ is reflected in the many human diseases (termed ciliopathies) that are caused by mutations in TZ complexes.

Here, we present the most systematic analysis of the TZ in any organism to date. We use a new proteomics technique to find trypanosome TZ proteins and then leverage this proteome to uncover basic TZ biology. We show that TZ proteins, including members of ciliopathy complexes, localize to different TZ sub-domains. Analysis using RNAi and HaloTag fusion protein approaches reveals that most TZ proteins (including the Meckel Syndrome ciliopathy complex) show long-term stable association with the TZ, whereas the Bardet-Biedl syndrome complex is dynamic.

RNAi depletion of these proteins causes a range of phenotypes, ranging from no cytological perturbation to absence of the central pair of microtubules and complete absence of the flagellum. This highlights the importance and variety of functions of this flagellum sub-compartment.