Mammalian γ2 AMPK regulates intrinsic heart rate.

ABSTRACT: AMPK is a conserved serine/threonine kinase whose activity maintains cellular energy homeostasis. Eukaryotic AMPK exists as αβγ complexes, whose regulatory γ subunit confers energy sensor function by binding adenine nucleotides. Humans bearing activating mutations in the γ2 subunit exhibit a phenotype including unexplained slowing of heart rate (bradycardia). Here, we show that γ2 AMPK activation downregulates fundamental sinoatrial cell pacemaker mechanisms to lower heart rate, including sarcolemmal hyperpolarization-activated current (I _f) and ryanodine receptor-derived diastolic local subsarcolemmal Ca²⁺ release. In contrast, loss of γ2 AMPK induces a reciprocal phenotype of increased heart rate, and prevents the adaptive intrinsic bradycardia of endurance training

SUBMITTER: Yavari A 

PROVIDER: S-EPMC5668267 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature