Regulation of phosphorylation of nicotinic acetylcholine receptors in mouse BC3H1 myocytes.
AUTOR(ES)
Smith, M M
RESUMO
By using 32P-labeling methods and performing immunoprecipitations with specific antibodies, we have found that three subunits of the nicotinic acetylcholine receptor are phosphorylated in mouse skeletal muscle cells. In nonstimulated cells, the molar ratios of phosphate estimated in alpha, beta, and delta subunits were 0.02, 0.05, and 0.5, respectively. All three subunits contained predominantly phosphoserine with some phosphothreonine; the beta subunit also contained phosphotyrosine. Incubating cells with agents that stimulate cAMP-dependent pathways (isoproterenol, forskolin, 8-Br-cAMP) increased the phosphorylation of the delta subunit by 50%, but phosphate labeling of the beta subunit was depressed by a third. In contrast, when cells were incubated with the divalent cation ionophores A-23187 or ionomycin, phosphorylation of both the delta and beta subunits increased. The results indicate that acetylcholine receptors are phosphorylated to significant levels in skeletal muscle cells and that cAMP-dependent and Ca2+-dependent pathways exist for controlling the phosphorylation state of the receptor subunits.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=299127Documentos Relacionados
- Activation of acetylcholine receptors on clonal mammalian BC3H-1 cells by high concentrations of agonist.
- Activation of acetylcholine receptors on clonal mammalian BC3H-1 cells by low concentrations of agonist.
- Protein degradation and increased mRNAs encoding proteins of the ubiquitin-proteasome proteolytic pathway in BC3H1 myocytes require an interaction between glucocorticoids and acidification.
- Anti-inositolglycan antibodies selectively block some of the actions of insulin in intact BC3H1 cells.
- Neurotransmitter regulation of neural development: acetylcholine and nicotinic receptors