10.25376/hra.7819961.v1 Priscila Y. Sato Priscila Y. Sato J. Kurt Chuprun J. Kurt Chuprun Laurel A. Grisanti Laurel A. Grisanti Meryl C. Woodall Meryl C. Woodall Brett R. Brown Brett R. Brown Rajika Roy Rajika Roy Christopher J. Traynham Christopher J. Traynham Jessica Ibetti Jessica Ibetti Anna M. Lucchese Anna M. Lucchese Ancai Yuan Ancai Yuan Konstantinos Drostatos Konstantinos Drostatos Douglas G. Tilley Douglas G. Tilley Erhe Gao Erhe Gao Walter J. Koch Walter J. Koch Restricting mitochondrial GRK2 post-ischemia confers cardioprotection by reducing myocyte death and maintaining glucose oxidation.pdf Health Research Alliance 2019 GRK2 Mitochondria Ischemia/Reperfusion Injury Heart Cardiology (incl. Cardiovascular Diseases) 2019-03-08 13:51:25 Journal contribution https://hra.figshare.com/articles/journal_contribution/Restricting_mitochondrial_GRK2_post-ischemia_confers_cardioprotection_by_reducing_myocyte_death_and_maintaining_glucose_oxidation_pdf/7819961 Increased abundance of GRK2 [G protein–coupled receptor (GPCR) kinase 2] is associated with poor cardiac function in heart failure patients. In animal models, GRK2 contributes to the pathogenesis of heart failure after ischemia-reperfusion (IR) injury. In addition to its role in down-regulating activated GPCRs, GRK2 also localizes to mitochondria both basally and post-IR injury, where it regulates cellular metabolism. We previously showed that phosphorylation of GRK2 at Ser670 is essential for the translocation of GRK2 to the mitochondria of cardiomyocytes post-IR injury in vitro and that this localization promotes cell death. Here, we showed that mice with a S670A knock-in mutation in endogenous GRK2 showed reduced cardiomyocyte death and better cardiac function post-IR injury. Cultured GRK2-S670A knock-in cardiomyocytes subjected to IR in vitro showed enhanced glucose-mediated mitochondrial respiratory function that was partially due to maintenance of pyruvate dehydrogenase activity and improved glucose oxidation. Thus, we propose that mitochondrial GRK2 plays a detrimental role in cardiac glucose oxidation post-injury.