Class-III neuronal intermediate filament protein (By similarity). May form an independent structural network without the involvement of other neurofilaments or may cooperate with the neuronal intermediate filament proteins NEFL, NEFH, NEFM and INA to form a filamentous network (PubMed:15322088, PubMed:15446584). Assembly of the neuronal intermediate filaments may be regulated by RAB7A (By similarity). Plays a role in the development of unmyelinated sensory neurons (By similarity). May be involved in axon elongation and axon regeneration after injury (By similarity). Inhibits neurite extension in type II spiral ganglion neurons in the cochlea (By similarity). {ECO:0000250|UniProtKB:P15331, ECO:0000250|UniProtKB:P21807, ECO:0000269|PubMed:15322088, ECO:0000269|PubMed:15446584}. This is the function of PRPH (peripherin, ENSG00000135406).