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Trypanosome TOR complex 2 functions in cytokinesis

Antonio Barquilla1, Miguel Navarro

  • 1Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, CSIC, (Spanish National Research Council), Avda. del Conocimiento s/n, Granada, Spain.

Cell Cycle (Georgetown, Tex.)
|February 18, 2009
PubMed

Insights

Target of rapamycin (TOR) proteins regulate cell growth in eukaryotes. In Trypanosoma brucei, TbTOR1 controls cell cycle and protein synthesis, while TbTOR2 is crucial for cell polarization, endocytosis, and cytokinesis.

Area of Science:

  • Cell Biology
  • Parasitology
  • Molecular Biology

Background:

  • The target of rapamycin (TOR) pathway is a critical regulator of cell growth, metabolism, and survival in eukaryotes.
  • Understanding TOR function in diverse organisms like Trypanosoma brucei provides insights into conserved and divergent cellular processes.

Purpose of the Study:

  • To identify and characterize TOR orthologs in Trypanosoma brucei.
  • To investigate the specific roles of TbTOR1 and TbTOR2 in trypanosome cell biology.
  • To explore the mechanism of rapamycin action in T. brucei.

Main Methods:

  • Identification and characterization of TOR orthologs in T. brucei.
  • Depletion studies to assess the function of TbTOR1 and TbTOR2.
  • Analysis of rapamycin's effect on T. brucei cell growth and TOR complex formation.

Main Results:

  • Two functional TOR orthologs (TbTOR1, TbTOR2) and two related proteins were identified in T. brucei.
  • TbTOR1 depletion caused G1 arrest and inhibited protein synthesis.
  • TbTOR2 depletion resulted in defects in cell polarization, endocytosis, and cytokinesis.
  • Rapamycin inhibited T. brucei growth by preventing TORC2 complex formation, uniquely affecting TORC2 but not TORC1.

Conclusions:

  • TbTOR1 and TbTOR2 play distinct and essential roles in regulating cell growth, protein synthesis, and cytokinesis in T. brucei.
  • T. brucei exhibits unique TOR signaling, with rapamycin specifically inhibiting TORC2.
  • TOR proteins are key regulators of cell growth and cytokinesis in T. brucei, potentially influencing developmental differentiation.

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