Parsons M, Valentine M, Deans J, Schieven G L, Ledbetter J A
Seattle Biomedical Research Institute, WA 98109.
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.
酪氨酸磷酸化的调节是控制高等真核生物生长和分化的关键因素。我们已经确定，在真核生物谱系中早期分化的原生动物布氏锥虫拥有多种能与特定抗磷酸酪氨酸抗血清发生反应的蛋白质。二维电泳显示，[32P]正磷酸盐标记细胞的抗磷酸酪氨酸免疫沉淀物中含有磷酸酪氨酸。对生命周期不同阶段细胞的蛋白质免疫印迹分析表明，在从细长型向粗短型血液形态转变过程中，40 - 42 kDa的酪氨酸磷酸化蛋白出现。原循环型细胞在原钒酸盐中生长导致特定酪氨酸磷酸化蛋白水平升高。布氏锥虫中含磷酸酪氨酸蛋白的证明及其在生命周期中的差异调节表明，酪氨酸激酶和磷酸酶可能在原始原生动物的生物学中发挥重要作用。
