Specific and innervation-regulated expression of the intermediate filamentprotein nestin at neuromuscular and myotendinous junctions in skeletal muscle
S. Vaittinen et al., Specific and innervation-regulated expression of the intermediate filamentprotein nestin at neuromuscular and myotendinous junctions in skeletal muscle, AM J PATH, 154(2), 1999, pp. 591-600
Citations number
26
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Medical Research Diagnosis & Treatment
The intermediate filament proteins nestin, vimentin, and desmin show a spec
ific temporal expression pattern during the development of myofibers from m
yogenic precursor cells. Nestin and vimentin are actively expressed during
early developmental stages to be later down-regulated, vimentin completely
and nestin to minimal levels, whereas desmin expression begins later and is
maintained in mature myofibers, in which desmin participates in maintainin
g structural integrity. In this study we have analyzed the expression level
s and distribution pattern of nestin in intact and denervated muscle in rat
and in human. Nestin immunoreactivity was specifically and focally localiz
ed in the sarcoplasm underneath neuromuscular junctions (NMJs) and in the v
icinity of the myotendinous junctions (MTJs), ie, in regions associated wit
h acetylcholine receptors (AChRs). This association prompted us to analyze
nestin in neurogenically and myogenically denervated muscle. Immunoblot ana
lysis disclosed a marked overall increase of accumulated nestin protein. Si
milar to the extrajunctional redistribution of AChRs in denervated myofiber
s, nestin immunoreactivity extended widely beyond the NMJ region. Re-innerv
ation caused complete reversion of these changes. Our study demonstrates th
at the expression levels and distribution pattern of nestin are regulated b
y innervation, ie, signal transduction into myofibers.