Neurofilament homeostasis and motoneurone degeneration.

Neurofilament disorganisation is a hallmark of various neurodegenerative diseases. We review here current knowledge of neurofilament structure, gene expression and function. Neurofilament involvement in motoneurone neurological diseases is discussed in view of recent data from transgenic and spontaneous mouse mutants. In the mammalian neurone, the three neurofilament subunits are assembled into intermediate filaments as obligate heteropolymers. The subunits are expressed differentially during development and adult life according to the cell type and its physiological state. In addition to the well-established role of neurofilaments in the control of axonal calibre, there is increasing evidence that neurofilaments can interact with other cytoskeletal components and can modulate the axoplasmic flow. Although the extent to which neurofilament abnormalities contribute to the pathogenesis in human diseases remains unknown, emerging evidence suggests that disorganised neurofilaments can provoke degeneration and death of neurones. BioEssays 23:24-33, 2001.