Stratton K R, Worley P F, Litz J S, Parsons S J, Huganir R L, Baraban J M
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
J Neurochem. 1991 Jan;56(1):147-52. doi: 10.1111/j.1471-4159.1991.tb02574.x.
Recent studies have identified protein tyrosine phosphorylation as a major intracellular signaling pathway. However, little is known about regulation of this signaling pathway in neuronal systems. To help identify changes in levels of protein tyrosine phosphorylation in brain, we have utilized specific anti-phosphotyrosine antibodies to detect phosphotyrosine-containing proteins by immunoblotting techniques. We have found that electroconvulsive treatment induces a selective increase in tyrosine phosphorylation of a soluble 40-kDa protein. The rise is rapid and transient, reaching maximal levels at 1-2 min and returning to basal levels by 8 min. The phosphotyrosine-containing 40-kDa protein is most prominent in hippocampus, smaller in neocortex, and not detected in brainstem or cerebellum. A phosphotyrosine-containing 42-kDa protein present in several cell types has recently been identified as a serine/threonine phosphotransferase, referred to as microtubule-associated protein 2 kinase. Comparison of the levels of tyrosine phosphorylation of the 40-kDa protein and microtubule-associated protein 2 kinase activity during column chromatography of hippocampal extracts demonstrates that the phosphotyrosine-containing 40-kDa protein and microtubule-associated protein 2 co-purify. Moreover, the tyrosine phosphorylation of the 40-kDa protein and microtubule-associated protein 2 kinase activity are increased to a similar extent following electroconvulsive treatment. These findings suggest that the phosphotyrosine-containing 40-kDa protein identified in brain is closely related to microtubule-associated protein 2 kinase.
最近的研究已确定蛋白质酪氨酸磷酸化是主要的细胞内信号传导途径。然而，对于该信号传导途径在神经元系统中的调节知之甚少。为了帮助确定脑中蛋白质酪氨酸磷酸化水平的变化，我们利用特异性抗磷酸酪氨酸抗体通过免疫印迹技术检测含磷酸酪氨酸的蛋白质。我们发现电惊厥治疗可诱导一种可溶性40 kDa蛋白质的酪氨酸磷酸化选择性增加。这种增加迅速且短暂，在1 - 2分钟时达到最高水平，8分钟时恢复到基础水平。含磷酸酪氨酸的40 kDa蛋白质在海马体中最为显著，在新皮质中较小，在脑干或小脑中未检测到。最近已确定几种细胞类型中存在的一种含磷酸酪氨酸的42 kDa蛋白质是一种丝氨酸/苏氨酸磷酸转移酶，称为微管相关蛋白2激酶。在海马提取物的柱色谱分析过程中，比较40 kDa蛋白质的酪氨酸磷酸化水平和微管相关蛋白2激酶活性，结果表明含磷酸酪氨酸的40 kDa蛋白质与微管相关蛋白2共纯化。此外，电惊厥治疗后，40 kDa蛋白质的酪氨酸磷酸化和微管相关蛋白2激酶活性增加到相似程度。这些发现表明，在脑中鉴定出的含磷酸酪氨酸的40 kDa蛋白质与微管相关蛋白2激酶密切相关。
