NEDL1 is a 1,606 amino acid cytoplasmic protein predominantly expressed in neurons of adult and fetal brain. NEDL1 functions as an E3 ubiquitin-protein ligase that, characteristic of E3 ligase proteins, accepts ubiquitin (in the form of a thioester) from an E2 ubiquitin-conjugating enzyme and transfers that ubiquitin residue to substrates targeted for degradation. NEDL1 mediates ubiquitination and subsequent degradation of Dvl-1 and targets mutant SOD-1. NEDL1 forms cytotoxic aggregates with Dvl, TRAP-?and mutant SOD1 that lead to motor neuron death in FALS (familial amyotrophic lateral sclerosis). individuals affect by FALS (also known as Lou Gehrig's disease) experience muscle weakness and atrophy throughout the body. FALS is caused by the degeneration of upper and lower motor neurons resulting in loss of signal to muscles.