Neurofilaments at a glance.

Neurofilaments (NFs) are intermediate filaments with a diameter of 10 nm, similar to that of neurons. Although they are present in perikarya and dendrites, neurofilaments are particularly abundant in axons, where they are essential for the radial growth of axons during development, the maintenance of axon caliber and the transmission of electrical impulses along axons, i.e. velocity of nerve conduction (Eyer and Peterson, 1994; Friede and Samorajski, 1970; Ohara et al., 1993; Yum et al., 2009; Zhu et al., 1997). In some pathological conditions, neurofilaments can accumulate in large numbers within cell bodies and proximal axons of affected neurons (Liu et al., 2009; Munoz et al., 1988). In patients with amyotrophic lateral sclerosis (ALS), these accumulations are a hallmark pathological lesion, but they are also prominent in sufferers of other neurological diseases, such as CharcotMarie-Tooth (CMT) disease, neurofilament inclusion disease (NFID), giant axonal neuropathy (GAN), diabetic neuropathy, spinal muscular atrophy (SMA) and spastic paraplegia, and are present in those people that suffer from Alzheimer’s disease (AD) and Parkinson’s disease (PD) (Abe et al., 2009; Perrot and Eyer, 2009; Szaro and Strong, 2010). Transgenic mouse models support the idea that these aberrant NF accumulations contribute to the death of the affected neurons, rather than simply being by-products of the pathogenic process (Côté et al., 1993; Couillard-Després et al., 1998; Williamson et al., 1998). In this Cell Science at a Glance article, we review the current understanding of neurofilament functions in health and disease.