A Role for Mitochondrial Protein AFG3L2 in Axonal Development

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A Role for Mitochondrial Protein AFG3L2 in Axonal Development

http://www.medicalnewstoday.com/articles/100341.php

Francesca Maltecca, Asadollah Aghaie, G. Schroeder,

Cassina, A. , J. , chiara

Malaguti, Stefano Previtali, Jean-Louis Guénet, Angelo Quattrini,

A. , and Giorgio Casari

Mitochondrial dysfunction has been implicated in several

neurodegenerative diseases, including hereditary spastic paraplegia

(HSP). HSP is characterized by degeneration of corticospinal axons,

which results in spasticity of the legs. Many genetic mutations have

been implicated in HSP, including defects in paraplegin, a component

of m-AAA protease, which resides in the inner mitochondrial membrane

and is involved in assembly and degradation of respiratory chain

proteins. Maltecca et al. discovered that in mice, mutations in

AFG3L2, the other component of m-AAA protease, resulted in

progressive paralysis and death by postnatal day 16. This paralysis

did not appear to result from axon degeneration, but rather from

impaired development of the corticospinal tract. Axons had smaller

diameters, likely because they had fewer neurofilaments, and more

axons were unmyelinated in mutants than in controls. Basal

respiratory rates were normal in the brains of mutant mice, but

metabolism involving respiratory complexes I and III was impaired.