Lateral motion of fluorescently labeled acetylcholine receptors in membranes of developing muscle fibers.

AUTOR(ES)

Axelrod, D

RESUMO

We have made direct, quantitative measurements of the lateral motion and age-dependent distribution of acetylcholine receptors (AChR) on the surface of rat myotubes in primary culture. AChR were fluorescently marked with tetramethylrhodamine-labeled alpha-bungarotoxin and AChR lateral motion was measured by the fluoresence photobleaching recovery technique. We found two coexisting distinct classes of AChR: (i) mobile, uniformly distributed AChR that appear on all myotubes shortly after fusion from myoblasts; and (ii) immobile, dense, highly granular AChR in patches of 10-60 mum size that appear shortly after fusion and disappear after myotubes have become extensively interconnected. In addition, evidence of turnover of AChR labeled with tetramethylrhodamine-alpha-bungarotoxin is seen in the gradual internalization of surface fluorescence within 36 hr after labeling. The relevance of these results to an understanding of the membrane dynamics and localization of muscle AChR is discussed.

Documentos Relacionados

• Lateral motion of beta receptors in membranes of cultured liver cells.
• Orientation of intermediate nucleotide states of indane dione spin-labeled myosin heads in muscle fibers.
• Equilibration and exchange of fluorescently labeled molecules in skinned skeletal muscle fibers visualized by confocal microscopy.
• Polarization of fluorescently labeled myosin subfragment-1 fully or partially decorating muscle fibers and myofibrils.
• Transformation by Rous sarcoma virus prevents acetylcholine receptor clustering on cultured chicken muscle fibers.