Regulation of cardiac cAMP synthesis and contractility by nucleoside diphosphate kinase B/G protein βγ dimer complexes

• Verfasst von: Hippe, Hans-Jörg [VerfasserIn]
• Verfasst von: Luedde, Mark [VerfasserIn]
• Verfasst von: Lutz, Susanne [VerfasserIn]
• Verfasst von: Koehler, Henrike [VerfasserIn]
• Verfasst von: Eschenhagen, Thomas [VerfasserIn]
• Verfasst von: Frey, Norbert [VerfasserIn]
• Verfasst von: Katus, Hugo [VerfasserIn]
• Verfasst von: Wieland, Thomas [VerfasserIn]
• Verfasst von: Niroomand, Feraydoon [VerfasserIn]
• Titel: Regulation of cardiac cAMP synthesis and contractility by nucleoside diphosphate kinase B/G protein βγ dimer complexes
• Verf.angabe: Hans-Joerg Hippe, Mark Luedde, Susanne Lutz, Henrike Koehler, Thomas Eschenhagen, Norbert Frey, Hugo A. Katus, Thomas Wieland, and Feraydoon Niroomand
• E-Jahr: 2007
• Jahr: 15 March 2007
• Umfang: 9 S.
• Fussnoten: Gesehen am 24.03.2022
• Titel Quelle: Enthalten in: Circulation research
• Ort Quelle: New York, NY : Assoc., 1953
• Jahr Quelle: 2007
• Band/Heft Quelle: 100(2007), 8, Seite 1191-1199
• ISSN Quelle: 1524-4571
• DOI: doi:10.1161/01.RES.0000264058.28808.cc
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: cAMP
• Sach-SW: cardiomyocytes
• Sach-SW: contractility
• Sach-SW: G proteins
• Sach-SW: NDPK
• K10plus-PPN: 1796561533

Abstract

Heterotrimeric G proteins are pivotal regulators of myocardial contractility. In addition to the receptor-induced GDP/GTP exchange, G protein α subunits can be activated by a phosphate transfer via a plasma membrane-associated complex of nucleoside diphosphate kinase B (NDPK B) and G protein βγ-dimers (Gβγ). To investigate the physiological role of this phosphate transfer in cardiomyocytes, we generated a Gβ1γ2-dimer carrying a single amino acid exchange at the intermediately phosphorylated His-266 in the β1 subunit (Gβ1H266Lγ2). Recombinantly expressed Gβ1H266Lγ2 were integrated into heterotrimeric G proteins in rat cardiomyocytes but were deficient in intermediate Gβ phosphorylation. Compared with wild-type Gβ1γ2 (Gβ1WTγ2), overexpression of Gβ1H266Lγ2 suppressed basal cAMP formation up to 55%. A similar decrease in basal cAMP production occurred when the formation of NDPK B/Gβγ complexes was attenuated by siRNA-mediated NDPK B knockdown. In adult rat cardiomyocytes expressing Gβ1H266Lγ2, the basal contractility was suppressed by ≈50% which correlated to similarly reduced basal cAMP levels and reduced Ser16-phosphorylation of phospholamban. In the presence of the β-adrenoceptor agonist isoproterenol, the total cAMP formation and contractility were significantly lower in Gβ1H266Lγ2 than in Gβ1WTγ2 expressing cardiomyocytes. However, the relative isoproterenol-induced increased was not affected by Gβ1H266Lγ2. We conclude that the receptor-independent activation of G proteins via NDPK B/Gβγ complexes requires the intermediate phosphorylation of G protein β subunits at His-266. Our results highlight the histidine kinase activity of NDPK B for Gβ and demonstrate its contribution to the receptor-independent regulation of cAMP synthesis and contractility in intact cardiomyocytes.