苦参碱对K562细胞蛋白酪氨酸激酶及磷酸酶活性的影响

Effects of Matrine on the Activity of Protein Tyrosine Kinase and Phosphatase in K562 Cells

背景与目的:一定浓度的苦参碱能诱导K562细胞分化,本研究拟初步探讨其诱导分化的信号转导机制。方法:运用链亲和素-生物素放大系统结合的酶联免疫法,动态检测苦参碱作用于K562细胞后,K562细胞膜相及胞浆内的蛋白酪氨酸激酶和磷酸酶活性的变化。结果:苦参碱能抑制K562细胞内的蛋白酪氨酸激酶活性,在<0.1mg/ml的浓度范围内,抑制作用具有浓度依赖性。不同浓度的苦参碱对蛋白酪氨酸磷酸酶活性的影响无显著性差异。0.1mg/ml的苦参碱作用K562细胞后,伴随蛋白酪氨酸激酶的活性变化,蛋白酪氨酸磷酸酶的活性也有一个短暂的下降。结论:在苦参碱诱导K562细胞分化的过程中,涉及到蛋白酪氨酸激酶的活性改变。膜相中蛋白酪氨酸激酶的活性改变先于胞浆内的改变,提示有一个信号的跨膜转运过程。同时伴有蛋白酪氨酸磷酸酶的活性变化,反映了胞内的蛋白酪氨酸残基磷酸化与去磷酸化的即时调节机制。苦参碱对蛋白酪氨酸激酶活性的抑制作用具有特异性与饱和性的特点,还提示有相应的受体存在。

Background & Objective: The differentiation of K562 cells can be induced by a given concentration of matrine. This study was designed to investigate the mechanism of signal transduction in induced differentiation of K562 cells. Methods:ELISA coupled with streptavidin biotin system was used to dynamically detect the activity of protein tyrosine kinase and phosphatase in the cytoplasm and the membrane of K562 cells treated by matrine. Results:Matrine inhibited the activity of protein tyrosine kinase in K562 cells, and the inhibitive effect depended on matrine of the concentration within 0.1 mg/ml. The effects of different concentration of matrine on the protein tyrosine phosphatase activity had no significant difference. Activity of the protein tyrosine phosphatase decreased transiently accompanied with the activity of the protein tyrosine kinase in K562 cells treated with 0.1mg/ml matrine. Conclusions:The change of protein tyrosine kinase activity is involved in the differentiation of K562 cells induced by matrine. The tyrosine kinase activity in cell membrane decreased more rapidly than that in cell cytoplasm,suggesting there be a transmembrane signal transduction. The change of tyrosine phosphatase activity following the kinase indicates the real time regulation of phosphorylation and dephosphorylation. Moreover, the inhibitory effect of matrine on the protein tyrosine kinase shows the characters of specificity and saturation, suggesting the exist of matrine associated receptor in K562 cells.