Neurofilaments usually contain three intermediate filament proteins: NEFL, NEFM, and NEFH which are involved in the maintenance of neuronal caliber. May additionally cooperate with other neuronal intermediate filament proteins to form neuronal filamentous networks (By similarity). Forms homodimers (in vitro). NF-L is the most abundant of the three neurofilament proteins and, as the other nonepithelial intermediate filament proteins, it can form homomeric 10-nm filaments. Belongs to the intermediate filament family.