Journal of Neuroscience, Vol 2, 1760-1774, Copyright © 1982 by Society for Neuroscience
Formation of postsynaptic specializations induced by latex beads in cultured muscle cells
HB Peng and PC Cheng
An early event in the formation of neuromuscular junctions is an
accumulation of acetylcholine receptors (AChRs) in the postsynaptic
membrane. This concentration of receptors is essential for the
establishment of the synaptic transmission. Previously, we showed that
latex beads coated with positively charged polypeptide molecules can induce
the formation of AChR clusters at the bead-muscle contacts (Peng, H. B.,
P.-C. Cheng, and P. W. Luther (1981) Nature 292: 831- 834). In this study,
we demonstrate that, in addition to AChR clusters, a set of postsynaptic
specializations normally present at the adult neuromuscular junction also
develops at the bead-muscle contacts in the absence of nerve. These
specializations include the membrane-associated cytoplasmic density and its
associated thin (6- to 8-nm) filaments, clusters of intramembranous
particles, membrane invaginations, the basal lamina, and 60- to 100-nm
coated vesicles. Our results indicate that the mechanism for the formation
of the postsynaptic specializations is preprogramed in the muscle and can
be triggered by an interaction with polypeptide-coated latex beads. Thus,
this bead- muscle system can be used as a simple model for understanding
the postsynaptic development during synaptogenesis.