[G-proteins coupled receptors].

The superfamily of G protein-coupled receptors plays a major role in the transmission and amplification of extracellular stimuli. These membrane receptors have a common structure made of a single polypeptide chain including seven transmembrane spanning domains. The comparison of amino acid sequences of the various G protein-coupled receptors reveals several conserved amino acids and regions playing a key role in ligand binding, G protein coupling, and activation of intracellular second messengers. Mutations of amino acid sequences of seven transmembrane domain receptors and their coupled G proteins are responsible for various human diseases including certain kinds of cancer.