A Kinetoplastid-Specific Kinesin Is Required for Cytokinesis and for Maintenance of Cell Morphology in Trypanosoma Brucei

Mol Microbiol. 2012 Feb;83(3):565-78. doi: 10.1111/j.1365-2958.2011.07951.x. Epub 2012 Jan 4.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism
  • Cell Cycle
  • Cytokinesis*
  • Cytoskeleton / metabolism
  • Flagella / metabolism
  • Kinesin / genetics
  • Kinesin / metabolism*
  • Microtubules / metabolism
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • RNA Interference
  • Trypanosoma brucei brucei / cytology*
  • Trypanosoma brucei brucei / genetics
  • Tubulin / metabolism

Substances

  • Mitochondrial Proteins
  • Protozoan Proteins
  • Tubulin
  • Adenosine Triphosphatases
  • Kinesin