Maness P F, Aubry M, Shores C G, Frame L, Pfenninger K H
Department of Biochemistry, University of North Carolina School of Medicine, Chapel Hill 27514.
Proc Natl Acad Sci U S A. 1988 Jul;85(14):5001-5. doi: 10.1073/pnas.85.14.5001.
Differentiating rat neurons express high levels of the protooncogene product pp60c-src, a 60-kDa tyrosine kinase of unknown function encoded by c-src. pp60c-src was found to be concentrated at least 9-fold in membranes from a subcellular fraction of nerve growth cones, the motile tips of outgrowing neuronal processes. Indirect immunofluorescence staining of cultured chick retinal explants showed pp60c-src in neuronal growth cones and processes, with the antigen particularly concentrated in growth cones of long neurites. pp60c-src in growth cone membranes was an active tyrosine-specific protein kinase with elevated tyrosine-specific protein kinase activity and reduced electrophoretic mobility characteristic of the form of pp60c-src in central nervous system neurons. pp60c-src was present at lower levels in subcellular fractions from mature rat brain but synaptosomal membranes were not enriched. Preferential localization of an active form of pp60c-src in nerve growth cone membranes and persistence of pp60c-src in mature neurons suggest that this tyrosine kinase is important in growth cone-mediated neurite extension and synaptic plasticity.
分化的大鼠神经元表达高水平的原癌基因产物pp60c-src，它是一种由c-src编码的功能未知的60 kDa酪氨酸激酶。发现pp60c-src在神经生长锥（即正在生长的神经元突起的活动末端）的亚细胞组分的膜中至少浓缩了9倍。对培养的鸡视网膜外植体进行间接免疫荧光染色显示，pp60c-src存在于神经元生长锥和突起中，抗原特别集中在长神经突的生长锥中。生长锥膜中的pp60c-src是一种活性酪氨酸特异性蛋白激酶，具有升高的酪氨酸特异性蛋白激酶活性以及中枢神经系统神经元中pp60c-src形式所特有的电泳迁移率降低。pp60c-src在成熟大鼠脑的亚细胞组分中的含量较低，但突触体膜未富集。pp60c-src的活性形式在神经生长锥膜中的优先定位以及pp60c-src在成熟神经元中的持续存在表明，这种酪氨酸激酶在生长锥介导的神经突延伸和突触可塑性中很重要。
