title: A kinetoplastid-specific kinesin is required for cytokinesis and for maintenance of cell morphology in Trypanosoma brucei.
abstract: Kinesins are motor-based transport proteins that play diverse roles in various cellular processes. The trypanosome genome lacks the homologues of many conserved mitotic kinesins, but encodes a number of trypanosome-specific kinesins with unknown function. Here, we report the biochemical and functional characterization of TbKIN-C, a trypanosome-specific kinesin, which was initially identified through an RNAi screen for cytokinesis genes in T. brucei. TbKIN-C possesses in vitro ATPase activity and associates with cytoskeletal tubulin microtubules in vivo. It is distributed throughout the cytoskeleton with a focal enrichment at the posterior end of the cell during early cell cycle stages. RNAi of TbKIN-C resulted in distorted cell shape with an elongated posterior filled with tyrosinated tubulin microtubules. Silencing of TbKIN-C impaired the segregation of organelles and cytoskeletal structures and led to detachment of the new flagellum and a small portion of the cytoplasm. We also show that RNAi of TbKIN-C compromised cytokinesis and abolished the trans-localization of TbCPC1, a subunit of the chromosomal passenger complex, from the central spindle to the initiation site of cytokinesis. Our results suggest an essential role of TbKIN-C in maintaining cell morphology, likely through regulating microtubule dynamics at the posterior end of the cell.
authors.affiliation: Department of Microbiology & Molecular Genetics, University of Texas Medical School at Houston, TX 77030, USA.
authors.forename: Liu
authors.initials: L
authors.lastname: Hu
authors.forename: Huiqing
authors.initials: H
authors.lastname: Hu
authors.forename: Ziyin
authors.initials: Z
authors.lastname: Li
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle; D048749:Cytokinesis; D003599:Cytoskeleton / Q000378:metabolism; D005407:Flagella / Q000378:metabolism; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D014346:Trypanosoma brucei brucei / Q000166:cytology* / Q000235:genetics; D014404:Tubulin / Q000378:metabolism
chemical_list: D024101:Mitochondrial Proteins; D015800:Protozoan Proteins; D014404:Tubulin; D000251:Adenosine Triphosphatases; D016547:Kinesins