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Normal role of the low‐molecular‐weight neurofilament protein in mitochondrial dynamics and disruption in Charcot‐Marie‐Tooth disease
Author(s) -
Gentil Benoit J.,
Minotti Sandra,
Beange Madeleine,
Baloh Robert H.,
Julien JeanPierre,
Durham Heather D.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.11-196345
Subject(s) - mfn2 , neurofilament , mitochondrial fusion , mitochondrion , lmna , microbiology and biotechnology , biology , mutant , intermediate filament , cytoskeleton , knockout mouse , gene , genetics , mitochondrial dna , mutation , cell , immunology , immunohistochemistry
Intermediate filaments serve important structural roles, but other cellular functions are increasingly recognized. This study demonstrated normal function of the low‐molecular‐weight neurofilament protein (NFL) in mitochondrial dynamics and disruption in Charcot‐Marie‐Tooth disease (CMT) due to mutations in the Nefl gene. In motor neurons of spinal cord cultured from Nefl ‐knockout mice, mitochondrial length and the rate of fusion were decreased concomitant with increased motility. These parameters were normalized after expression of NFL wt on the Nefl ‐/‐ background, but not by overexpression of the profusion protein, mitofusin 2 (MFN2). The effects of CMT‐causing NFL mutants bore similarities to and differences from Nefl knockout. In the early phase of toxicity before disruption of the neurofilament network, NFL Q333P and NFL P8R integrated into neurofilaments and had effects on mitochondria similar to those with Nefl knockout. The reduction of fusion rate by NFL Q333P was partly due to interference with the function of the profusion protein MFN2, which is mutated in CMT2A, functionally linking these forms of CMT. In the later phase of toxicity, mitochondria essentially stopped moving in neurons expressing NFL mutants, probably a consequence of cytoskeletal disruption. Overall, the data point to important functions of neurofilaments in mitochondrial dynamics as well as primary involvement in CMT2E/1F.—Gentil, B. J. Minotti, S., Beange, M., Baloh, R. H., Julien, J.‐P., Durham, H. D. Normal role of the low‐molecular‐weight neurofilament protein in mitochondrial dynamics and disruption in Charcot‐Marie‐Tooth disease. FASEB J. 26, 1194‐1203 (2012). www.fasebj.org