CHRM3 Gene: Function, Expression, and Disease Associations | Biomedical SEO

The CHRM3 gene encodes the M3 muscarinic acetylcholine receptor, a member of the G protein-coupled receptor (GPCR) family. M3 receptors are widely expressed in smooth muscle, glands, and the central nervous system. They mediate cholinergic responses such as smooth muscle contraction, glandular secretion, and modulation of neuronal excitability. Activation of M3 receptors typically couples to Gq/11 proteins, leading to phospholipase C activation, inositol trisphosphate production, and intracellular calcium mobilization. CHRM3 is involved in various physiological processes and has been implicated in multiple diseases, including neurological disorders, metabolic conditions, and certain cancers.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Muscarinic acetylcholine receptor signaling

• Calcium signaling pathway

• Phospholipase C-mediated signaling

• GPCR downstream signaling

• Smooth muscle contraction pathway

The M3 muscarinic acetylcholine receptor is a 479-amino acid protein with seven transmembrane domains, typical of GPCRs. It is predominantly expressed in tissues with cholinergic innervation, such as smooth muscle, exocrine glands, and brain. Upon acetylcholine binding, the receptor undergoes conformational changes that activate Gq/11 proteins, triggering phospholipase C beta, which hydrolyzes phosphatidylinositol 4,5-bisphosphate to generate inositol trisphosphate and diacylglycerol. This leads to intracellular calcium release and protein kinase C activation, mediating contraction, secretion, and gene expression. Post-translational modifications include glycosylation and phosphorylation, which regulate receptor trafficking and desensitization. The receptor is a target for anticholinergic drugs used in respiratory, urinary, and gastrointestinal disorders.