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Evidence of Tyrosine Kinase Activity in the Protozoan Parasite Trypanosoma brucei
Author(s) -
WHEELERALM ELIZABETH,
SHAPIRO STUART Z.
Publication year - 1992
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1992.tb01473.x
Subject(s) - biology , protein tyrosine phosphatase , tyrosine kinase , tyrosine phosphorylation , trypanosoma brucei , platelet derived growth factor receptor , tyrosine , phosphorylation , biochemistry , trypanosoma brucei rhodesiense , receptor tyrosine kinase , microbiology and biotechnology , signal transduction , growth factor , receptor , gene
. Phosphorylation of proteins at tyrosine is an important mechanism for regulating cell growth and proliferation in metazoan organisms. In this report, we have demonstrated that Trypanosoma brucei , a protozoan parasite, possesses a tyrosine kinase that plays a role in regulation of proliferation of this protozoan. Genistein, a tyrosine kinase inhibitor, prevented multiplication of the parasite. An in vitro kinase assay demonstrated the presence of a kinase capable of phosphorylating an exogenous substrate at tyrosine, and genistein was able to reduce trypanosome‐mediated phosphorylation of this substrate. An alkali digestion of 32 P‐labeled trypanosome proteins separated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis indicated several proteins phosphorylated at tyrosine. These results indicate that T. brucei has a tyrosine kinase that is involved in proliferation or growth regulation of the parasite and provide further evidence for the possibility of growth factor regulation and signal transduction in trypanosomes.