Distinct patterns of tyrosine phosphorylation during the life cycle of Trypanosoma brucei

Mol Biochem Parasitol. 1991 Apr;45(2):241-8. doi: 10.1016/0166-6851(91)90091-j.


Regulation of tyrosine phosphorylation is a critical element in controlling growth and differentiation in higher eukaryotes. We have determined that the protozoan Trypanosoma brucei, which diverged early in the eukaryotic lineage, possesses multiple proteins which react with a specific anti-phosphotyrosine antiserum. Anti-phosphotyrosine immunoprecipitates of [32P]orthophosphate-labeled cells were shown to contain phosphotyrosine by two-dimensional electrophoresis. Western analysis of cells from different stages of the life cycle demonstrates the appearance of tyrosine-phosphorylated proteins at 40-42 kDa during the transition from slender to stumpy blood-forms. Growth of procyclic form cells in orthovanadate resulted in increased levels of specific tyrosine-phosphorylated proteins. The demonstration of phosphotyrosine-containing proteins in T. brucei and their differential regulation during the life cycle suggests that tyrosine kinases and phosphatases may play an important role in the biology of primitive protozoa.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blotting, Western
  • Chromatography, Ion Exchange
  • Eflornithine / pharmacology
  • Electrophoresis, Polyacrylamide Gel
  • Phosphoprotein Phosphatases / metabolism*
  • Phosphorylation
  • Phosphotyrosine
  • Precipitin Tests
  • Protein Tyrosine Phosphatases
  • Protein-Tyrosine Kinases / analysis
  • Protein-Tyrosine Kinases / metabolism*
  • Rats
  • Trypanosoma brucei brucei / growth & development
  • Trypanosoma brucei brucei / metabolism*
  • Tyrosine / analogs & derivatives*
  • Tyrosine / metabolism
  • Vanadates / pharmacology


  • Phosphotyrosine
  • Vanadates
  • Tyrosine
  • Protein-Tyrosine Kinases
  • Phosphoprotein Phosphatases
  • Protein Tyrosine Phosphatases
  • Eflornithine