Immunocytochemical localization of ubiquitin at human neuromuscular junctions

Abstract
Using several specific monoclonal and polyclonal antibodies, we found that ubiquitin is highly concentrated in the post‐synaptic domain of human neuromuscular junctions. The distribution and pattern of ubiquitin immunoreactivity is identical to the localization of bound a‐bungarotoxin, suggesting that ubiquitin may be involved in post‐translational modification or turnover of the acetylcholine receptor or other junctional proteins of the muscle fibre.