Trypanosoma brucei Polo-like kinase is essential for basal body duplication, kDNA segregation and cytokinesis

Mol Microbiol. 2007 Sep;65(5):1229-48. doi: 10.1111/j.1365-2958.2007.05866.x. Epub 2007 Jul 27.


Polo-like kinases (PLKs) are conserved eukaryotic cell cycle regulators, which play multiple roles, particularly during mitosis. The function of Trypanosoma brucei PLK was investigated in procyclic and bloodstream-form parasites. In procyclic trypanosomes, RNA interference (RNAi) of PLK, or overexpression of TY1-epitope-tagged PLK (PLKty), but not overexpression of a kinase-dead variant, resulted in the accumulation of cells that had divided their nucleus but not their kinetoplast (2N1K cells). Analysis of basal bodies and flagella in these cells suggested the defect in kinetoplast division arose because of an inhibition of basal body duplication, which occurred when PLK expression levels were altered. Additionally, a defect in kDNA replication was observed in the 2N1K cells. However, the 2N1K cells obtained by each approach were not equivalent. Following PLK depletion, the single kinetoplast was predominantly located between the two divided nuclei, while in cells overexpressing PLKty, the kinetoplast was mainly found at the posterior end of the cell, suggesting a role for PLK kinase activity in basal body and kinetoplast migration. PLK RNAi in bloodstream trypanosomes also delayed kinetoplast division, and was further observed to inhibit furrow ingression during cytokinesis. Notably, no additional roles were detected for trypanosome PLK in mitosis, setting this protein kinase apart from its counterparts in other eukaryotes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Separation
  • Cytokinesis / physiology*
  • DNA Replication
  • DNA, Kinetoplast / metabolism*
  • Flagella / ultrastructure*
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • RNA Interference
  • Trypanosoma brucei brucei* / cytology
  • Trypanosoma brucei brucei* / enzymology
  • Trypanosoma brucei brucei* / physiology


  • Cell Cycle Proteins
  • DNA, Kinetoplast
  • Proto-Oncogene Proteins
  • Protozoan Proteins
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1