FAZ assembly in bloodstream form Trypanosoma brucei requires kinesin KIN-E

Trypanosoma brucei , the causative agent of African sleeping sickness, uses its flagellum for movement, cell division, and signaling. The flagellum is anchored to the cell body membrane via the flagellar attachment zone (FAZ), a complex of proteins, filaments, and microtubules that spans two membranes with elements on both flagellum and cell body sides. How FAZ components are carried into place to form this complex is poorly understood. Here, we show that the trypanosome-specific kinesin KIN-E is required for building the FAZ in bloodstream-form parasites. KIN-E is localized along the flagellum with a concentration at its distal tip. Depletion of KIN-E by RNAi rapidly inhibits flagellum attachment and leads to cell death. A detailed analysis reveals that KIN-E depletion phenotypes include failure in cytokinesis completion, kinetoplast DNA mis-segregation, and transport vesicle accumulation. Together with previously published results in procyclic form parasites, these data suggest KIN-E plays a critical role in FAZ assembly in T. brucei . ### Competing Interest Statement This work was funded in part by an unrestricted gift from the Strode and Douglas Family Charity Fund, which is administered by the Fidelity Charitable Gift Trust. One of the donors to this fund, Robert L. Douglas, is also the second author on this manuscript. This is mentioned in the Acknowledgements section. Mr. Douglas does not believe this constitutes a conflict of interest, as he does not receive compensation or payments from the University of California, has executed University of California intellectual property assignment forms, is not seeking intellectual property rights from this work, and does not stand to gain or lose financially from the publication of this work.