Fiore R S, Bayer V E, Pelech S L, Posada J, Cooper J A, Baraban J M
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Neuroscience. 1993 Jul;55(2):463-72. doi: 10.1016/0306-4522(93)90516-i.
Neurotransmitters and growth factors can trigger activation of a newly described family of mitogen-activated protein kinases. To help define the role of this kinase family in signal transduction in the nervous system, we have conducted immunohistochemical studies to localize p42 mitogen-activated protein kinase in rat brain sections. Light-microscopic studies revealed staining in neuronal cell bodies and dendrites that is particularly prominent in superficial layers of the neocortex, the hippocampal CA3 region and dentate gyrus, as well as cerebellar Purkinje cells. Discrete staining of oligodendrocytes was also apparent in fiber tracts, indicating expression of p42 mitogen-activated protein kinase in both neuronal and glial cell types. Electron-microscopic studies demonstrated that staining in dendrites is closely associated with microtubules. In the cell bodies, prominent staining was associated with the Golgi apparatus. In contrast, immunolabeling of synaptic terminals was not detected. Previous studies have demonstrated that p42 mitogen-activated protein kinase responds to neuronal stimulation. Immunohistochemical studies presented in this paper demonstrate prominent staining for this kinase in neuronal cell bodies and dendrites. Therefore, this kinase is likely to play a key role in postsynaptic signal transduction. As both p42 mitogen-activated protein kinase and microtubule-associated protein 2, an in vitro substrate of p42 mitogen-activated kinase, are associated with dendritic microtubules, this kinase may mediate effects of growth factors or neurotransmitters on the dendritic cytoskeleton.
神经递质和生长因子可触发一个新描述的丝裂原活化蛋白激酶家族的激活。为了帮助确定该激酶家族在神经系统信号转导中的作用，我们进行了免疫组织化学研究，以在大鼠脑切片中定位p42丝裂原活化蛋白激酶。光学显微镜研究显示，神经元细胞体和树突中有染色，在新皮质浅层、海马CA3区和齿状回以及小脑浦肯野细胞中尤为明显。少突胶质细胞在纤维束中也有离散染色，表明p42丝裂原活化蛋白激酶在神经元和胶质细胞类型中均有表达。电子显微镜研究表明，树突中的染色与微管密切相关。在细胞体中，明显的染色与高尔基体相关。相比之下，未检测到突触终末的免疫标记。先前的研究表明，p42丝裂原活化蛋白激酶对神经元刺激有反应。本文中的免疫组织化学研究表明，该激酶在神经元细胞体和树突中有明显染色。因此，该激酶可能在突触后信号转导中起关键作用。由于p42丝裂原活化蛋白激酶和微管相关蛋白2（p42丝裂原活化激酶的体外底物）均与树突微管相关，该激酶可能介导生长因子或神经递质对树突细胞骨架的作用。
