Regulation by ARIA/neuregulin of acetylcholine receptor gene transcription at the neuromuscular junction

Transcription of genes encoding nicotinic acetylcholine receptor (AChR) subunits (α, β, γ or ε, and δ) is highest in nuclei localized to the synaptic region of the muscle which contributes to maintain a high density of AChRs at the postjunctional membrane. ARIA (AChR inducing activity) is believed to be the trophic factor utilized by motor neurons to stimulate AChR synthesis in the subsynaptic area. ARIA stimulates tyrosine phosphorylation of the erbB proteins and activates the MAP kinase pathway which is required for the ARIA-mediated induction of AChR genes.