Primary structure and biochemical properties of an M2 muscarinic receptor

• Published in: Science (American Association for the Advancement of Science) 1987-05, Vol.236 (4801), p.600-605
• Main Authors: PERALTA, E. G, WINSLOW, J. W, PETERSON, G. L, SMITH, D. H, ASHKENAZI, A, RAMACHANDRAN, J, SCHIMERLIK, M. I, CAPON, D. J
• Format: Article
• Language: English
• Subjects: Acetylcholine; Acetylcholine receptors; Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; Cell Line; Cell receptors; Cell structures and functions; Cloning; DNA - genetics; Exons; Fundamental and applied biological sciences. Psychology; Genetic aspects; Glycoproteins; GTP-Binding Proteins - metabolism; Heart Atria - analysis; Immunosorbent Techniques; Membrane Proteins; Molecular and cellular biology; Molecular Weight; Nucleic Acid Hybridization; Peptide Fragments - metabolism; Quinuclidinyl Benzilate - metabolism; Receptors; Receptors, Muscarinic - genetics; Receptors, Muscarinic - metabolism; Sequence Homology, Nucleic Acid; Swine; Transfection
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.3107123

A partial amino acid sequence obtained for porcine atrial muscarinic acetylcholine receptor was used to isolate complementary DNA clones containing the complete receptor coding region. The deduced 466-amino acid polypeptide exhibits extensive structural and sequence homology with other receptors coupled to guanine nucleotide binding (G) proteins (for example, the beta-adrenergic receptor and rhodopsins); this similarity predicts a structure of seven membrane-spanning regions distinguished by the disposition of a large cytoplasmic domain. Stable transfection of the Chinese hamster ovary cell line with the atrial receptor complementary DNA leads to the binding of muscarinic antagonists in these cells with affinities characteristic of the M2 receptor subtype. The atrial muscarinic receptor is encoded by a unique gene consisting of a single coding exon and multiple, alternatively spliced 5' noncoding regions. The atrial receptor is distinct from the cerebral muscarinic receptor gene product, sharing only 38% overall amino acid homology and possessing a completely nonhomologous large cytoplasmic domain, suggesting a role for the latter region in differential effector coupling.