Glutamate Slows Axonal Transport of Neurofilaments in Transfected Neurons

• Published in: The Journal of cell biology 2000-07, Vol.150 (1), p.165-175
• Main Authors: Ackerley, Steven, Grierson, Andrew J., Brownlees, Janet, Thornhill, Paul, Anderton, Brian H., Leigh, P. Nigel, Shaw, Christopher E., Christopher C. J. Miller
• Format: Article
• Language: English
• Subjects: Alzheimer's disease; Alzheimers disease; Amyotrophic lateral sclerosis; Antibodies; Axonal Transport - drug effects; Axonal Transport - physiology; Axons; Biological Transport, Active - drug effects; Cells; Cells, Cultured; Glutamic Acid - metabolism; Glutamic Acid - pharmacology; Green Fluorescent Proteins; Humans; Luminescent Proteins - genetics; Mitogen-Activated Protein Kinases - metabolism; Nervous system diseases; Neurites; Neurites - metabolism; Neurofilament proteins; Neurofilament Proteins - genetics; Neurofilament Proteins - metabolism; Neurology; Neurons; Neurons - cytology; Neurons - enzymology; Original; Phosphorylation; Phosphorylation - drug effects; Proteins; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Transfection
• ISSN: 0021-9525; 1540-8140
• 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.