Wheeler-Alm E, Shapiro S Z
Department of Veterinary Pathobiology, University of Illinois, Urbana 61801.
J Protozool. 1992 May-Jun;39(3):413-6. doi: 10.1111/j.1550-7408.1992.tb01473.x.
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 32P-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.
蛋白质酪氨酸磷酸化是后生动物中调节细胞生长和增殖的重要机制。在本报告中，我们证明了原生动物寄生虫布氏锥虫拥有一种酪氨酸激酶，该激酶在调节这种原生动物的增殖中发挥作用。酪氨酸激酶抑制剂染料木黄酮可阻止该寄生虫的繁殖。体外激酶测定表明存在一种能够使外源性底物发生酪氨酸磷酸化的激酶，并且染料木黄酮能够减少锥虫介导的该底物的磷酸化。对经十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳分离的32P标记的锥虫蛋白质进行碱消化，结果表明有几种蛋白质发生了酪氨酸磷酸化。这些结果表明，布氏锥虫具有一种参与寄生虫增殖或生长调节的酪氨酸激酶，并为锥虫中生长因子调节和信号转导的可能性提供了进一步的证据。
