Résumé
Ca2+ channel auxiliary subunits have been suspected to play fundamental roles in channel function from their early biochemical characterization (see Chapter 4). Their strong association with the main α1 subunits and their role in the reconstitution of proper channel activity, were strong evidences for key functions. Later, the discovery of a whole family of β subunit genes, now counting four members, with regions of high similarity including channel binding sites as well as more ubiquitous protein-protein interaction domains, and expression studies challenging different combinations of calcium channel subunits, confirmed their modulatory functions in every aspect of channel activity, from expression and targeting to regulation by G-proteins. The discovery of neuropathologies linked to genetic defects in the β subunit gene constitutes one more argument for assigning to this auxiliary subunit a central role in channel function and regulation.