The exact function of Peripherin, or Neurofilament 4, is unknown however it has been suggested to play a role in axon formation and determining and maintaining the shape of nerve cells. Peripherin is a 470 amino acid Class-III neuronal intermediate filament protein. It has two isoforms produced by alternative splicing, one with a molecular weight of 53.651 KDa and one with a molecular weight of 53.779 KDa.