Carbohydrate requirement for expression and stability of acetylcholine receptor on the surface of embryonic muscle cells in culture.

Abstract

The significance of protein glycosylation for metabolism of acetylcholine receptors (AcChoR) in primary cultures of embryonic chicken muscle cells was investigated. Tunicamycin, a specific inhibitor of the glycosylation of asparagine residues on glycoproteins, decreased AcChoR accumulation and accelerated its degradation. There was no evidence that tunicamycin treatment affected AcChoR biosynthesis, intracellular transport or incorporation into surface membranes. Leupeptin, an inhibitor of intracellular proteases, markedly increased accumulation of AcChoR on the external surface of muscle cells treated with tunicamycin. Apparently, impairment of protein glycosylation prevents accumulation of AcChoR by increasing its susceptibility to degradation by cellular proteases.