Characterisation of G-protein-coupled receptors by antibodies

G-protein-coupled receptors constitute a superfamily of integral membrane proteins encompassing hundreds of receptors for all types of chemical messengers, as well as, for example, the key molecules of our light and smell sensory systems, bioactive amines, peptide hormones, neurotransmitters and even proteins. Because of their complicated organisation with the characteristic seven transmembrane segments (7 TM) it has yet been impossible to structurally characterise any G-protein coupled receptor by crystallography or magnetic resonance. However, a number of indirect methods to study the structure and ligand binding of these proteins have been developed. Various studies have shown that antibodies produced against G-protein-coupled receptors are valuable tools. In this review we focus on the use of anti-receptor antibodies for the characterisation of membranes, cells and tissue, for mapping of the binding site, for purification by immunoaffinity chromatography and for biochemical studies of G-protein-coupled receptors. As an example we describe the characterisation of the G-protein-coupled neuropeptide Y receptor subtypes.