• Ginger, Michael
• Harmer, Jane
• Drižytė, Kristina
• Hawkins, Erica
• Qi, Xin
• Kerry, Louise
• Mckean, Paul Gerard

Abstract

The tubulin cofactor C (TBCC) domain-containing protein TbRP2 is a basal body (centriolar) protein essential for axoneme formation in the flagellate protist Trypanosoma brucei, the causal agent of African sleeping sickness. Here, we show how TbRP2 is targeted and tethered at mature basal bodies and provide novel insight into TbRP2 function. Regarding targeting, understanding how several hundred proteins combine to build a microtubule axoneme is a fundamental challenge in eukaryotic cell biology. We show basal body localisation of TbRP2 is mediated by twinned, N-terminal TOF and LisH motifs, motifs that otherwise facilitate localisation of only a few, conserved proteins at microtubule-organising centres in animals, plants, and flagellate protists. Regarding TbRP2 function, there is debate as to whether the flagellar assembly function of specialised, centriolar TBCC-domain containing proteins is processing tubulin, the major component of axonemes, or general vesicular trafficking in a flagellum assembly context. Here we report TbRP2 is required for the recruitment of T. brucei orthologs of MKS1 and MKS6, proteins that in animal cells are part of a complex that assembles at the base of the flagellum to regulate protein composition and cilium function. We also identify that TbRP2 is detected by YL1/2, an antibody classically used to detect alpha-tubulin. Together these data suggest a general processing role for TbRP2 in trypanosome flagellum assembly and challenge the notion that TbRP2 functions solely in assessing tubulin ‘quality’ prior to tubulin incorporation into the elongating axoneme.

Topics

• impedance spectroscopy
• twinned