Translocation of G-protein beta3 subunit from the cytosol pool to the membrane pool by beta1-adrenergic receptor stimulation in perfused rat hearts.
To elucidate the intracellular function and localization of the heterotrimeric G-protein beta3 subunit (Gbeta3) in the heart, we studied the effects of subtype-specific beta-adrenergic receptor (beta-AR) stimulation on Gbeta3 localization using isoform-specific antibodies. The amount of Gbeta3 in the cytosol dramatically decreased in hearts perfused with isoproterenol (ISO) alone or ISO with ICI 118551, a beta2-AR antagonist. Propranolol or CGP 20712A, a beta1-AR antagonist, blocked the ISO-induced decrease in the Gbeta3 content of the cytosol. In contrast, Gbeta3 content of the membrane fraction significantly increased in hearts perfused with ISO alone or ISO with ICI 118551. We conclude that stimulation of the beta1-AR induces isoform-specific translocation of Gbeta3 from the cytosol to the membrane fraction in rat hearts.
Kageyama
K
K
Department of Cardiovascular Medicine, Hokkaido University, Hokkaido University School of Medicine, Sapporo, Japan.
Murakami
T
T
Iizuka
K
K
Sato
K
K
Ichihara
K
K
Tokumitsu
Y
Y
Kitabatake
A
A
Kawaguchi
H
H
D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism*; D013347:Subcellular Fractions
D018342:Receptors, Adrenergic, beta-1; D019204:GTP-Binding Proteins