LOCALIZATION OF CARDIAC G(S-ALPHA) IN TRANSGENIC MICE OVEREXPRESSING G(S-ALPHA)

The biochemical and physiological effects of G(S alpha) activation are well known; however, little is known about the anatomical localisatio n of G(S alpha) in the myocardium. Knowledge of the localisation might yield insights into G protein function in heart. The utility of immun ocytochemistry using immunofluorescent methods is limited in normal he arts because of the low expression of G(S alpha). In order to magnify the G(S alpha) signal, we studied transgenic mice overexpressing myoca rdial G(S alpha). Immunofluorescent techniques with confocal imaging u sing rabbit antiserum specific for G(S alpha) were studied in frozen s ections of mouse left ventricle. G(S alpha) labeling appeared to be lo calised to the T-tubules and intercalated disks in the G(S alpha) over expressing mouse hearts, whereas the control mice showed background fl uorescence with diffuse faint labeling. The localisation of G(S alpha) to structures involved in calcium handling and membrane conductance p laces G(S alpha) at a focal point in the regulation of these key funct ions. (C) 1997 Academic Press Limited.