HETEROLOGOUS EXPRESSION OF G-PROTEIN-COUPLED RECEPTORS - HUMAN OPIOIDRECEPTORS UNDER SCRUTINY

G-protein-coupled receptors whose topology shows seven transmembrane d omains form the largest known family of receptors involved in higher o rganism signal transduction. Despite increasing knowledge on the funct ioning mechanisms of these receptors, almost no structural data are av ailable but only a few models. Structural studies using a wide range o f physical and biochemical techniques may require fairly large (up to several milligrams) amounts of purified protein. Since such quantities are not naturally available, overexpression is prerequisite. Heterolo gous expression systems are then assayed for maximal production of a p rotein facsimile. Heterologous systems may also provide interesting al ternatives for receptor functional studies in a different cellular con text. Opioid receptors will be used as an example to discuss aspects r elated to the choice and suitability of several different expression s ystems for the intended analysis of G-protein-coupled receptor propert ies. General implications will be outlined ((C) Societe francaise de b iochimie et biologie moleculaire / Elsevier, Paris).