Ackerley S, Grierson A J, Brownlees J, Thornhill P, Anderton B H, Leigh P N, Shaw C E, Miller C C
Department of Neuroscience, The Institute of Psychiatry, Kings College London, London SE5 8AF United Kingdom.
J Cell Biol. 2000 Jul 10;150(1):165-76. doi: 10.1083/jcb.150.1.165.
Neurofilaments are transported through axons by slow axonal transport. Abnormal accumulations of neurofilaments are seen in several neurodegenerative diseases, and this suggests that neurofilament transport is defective. Excitotoxic mechanisms involving glutamate are believed to be part of the pathogenic process in some neurodegenerative diseases, but there is currently little evidence to link glutamate with neurofilament transport. We have used a novel technique involving transfection of the green fluorescent protein-tagged neurofilament middle chain to measure neurofilament transport in cultured neurons. Treatment of the cells with glutamate induces a slowing of neurofilament transport. Phosphorylation of the side-arm domains of neurofilaments has been associated with a slowing of neurofilament transport, and we show that glutamate causes increased phosphorylation of these domains in cell bodies. We also show that glutamate activates members of the mitogen-activated protein kinase family, and that these kinases will phosphorylate neurofilament side-arm domains. These results provide a molecular framework to link glutamate excitotoxicity with neurofilament accumulation seen in some neurodegenerative diseases.
神经丝通过轴突慢速运输在轴突内进行转运。在几种神经退行性疾病中可见神经丝的异常积聚，这表明神经丝运输存在缺陷。涉及谷氨酸的兴奋性毒性机制被认为是某些神经退行性疾病致病过程的一部分，但目前几乎没有证据将谷氨酸与神经丝运输联系起来。我们使用了一种新技术，即转染绿色荧光蛋白标记的神经丝中链，来测量培养神经元中的神经丝运输。用谷氨酸处理细胞会导致神经丝运输减慢。神经丝侧臂结构域的磷酸化与神经丝运输减慢有关，并且我们发现谷氨酸会导致细胞体中这些结构域的磷酸化增加。我们还表明谷氨酸会激活丝裂原活化蛋白激酶家族的成员，并且这些激酶会使神经丝侧臂结构域磷酸化。这些结果提供了一个分子框架，将谷氨酸兴奋性毒性与某些神经退行性疾病中所见的神经丝积聚联系起来。
