PT  - JOURNAL ARTICLE
AU  - Carlo Sala
AU  - James O’Malley
AU  - Rufeng Xu
AU  - Guido Fumagalli
AU  - Miriam M. Salpeter
TI  - ε Subunit-Containing Acetylcholine Receptors in Myotubes Belong to the Slowly Degrading Population
AID  - 10.1523/JNEUROSCI.17-23-08937.1997
DP  - 1997 Dec 01
TA  - The Journal of Neuroscience
PG  - 8937--8944
VI  - 17
IP  - 23
4099  - http://www.jneurosci.org/content/17/23/8937.short
4100  - http://www.jneurosci.org/content/17/23/8937.full
SO  - J. Neurosci.1997 Dec 01; 17
AB  - Two types of muscle acetylcholine receptors (AChRs) can be distinguished on the basis of their degradation rates and sensitivities to innervation, muscle activity, and agents elevating intracellular cAMP. The first type (Rs), is present in a stable form (degradationt½ = ∼10 d) at the adult innervated neuromuscular junctions (NMJs). Rs can also exist in a less stable form (called accelerated Rs;t½ = ∼3–5 d) at denervated NMJs and in aneurally cultured myotubes; agents that increase intracellular cAMP reversibly modulate Rs stability. The second type of AChR is a rapidly degrading receptor (Rr) expressed only in embryonic and noninnervated muscles. Rr can be stabilized by ATP and not by cAMP. This study tested the hypothesis that the degradation properties unique to the Rs are attributable to the presence of the ε subunit.Immunoprecipitation and Western blot analysis of AChRs extracted from rat muscle cells in tissue culture showed that AChRs recognized by antibodies against the ε subunit degraded as a single population with a half-life similar to that of the slow component, Rs, in these cells. In addition, as for Rs receptors in denervated NMJs and cultured muscle cell, the degradation rate of these ε-containing AChRs was stabilized by dibutyryl-cAMP. The data indicate that the ε-containing AChRs behave like Rs. Thus, the presence of the ε subunit is sufficient for selecting an AChR molecule to the Rs pool.