AUTHOR=Porro Alessandro , Thiel Gerhard , Moroni Anna , Saponaro Andrea 

TITLE=cyclic AMP Regulation and Its Command in the Pacemaker Channel HCN4

JOURNAL=Frontiers in Physiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.00771

DOI=10.3389/fphys.2020.00771

ISSN=1664-042X

ABSTRACT=<p>Direct regulation of the pacemaker “funny” current (I<sub>f</sub>) by cyclic AMP (cAMP) underlies heart rate modulation by the autonomic nervous system. At the molecular level, cAMP activates hyperpolarization-activated cyclic nucleotide-gated (HCN) channels that drive I<sub>f</sub> in sinoatrial node (SAN) myocytes. Even though HCN channel genes were identified more than 20 years ago, the understanding of how cAMP regulates their gating is still fragmented. Here we summarize present understanding on how the cAMP signal is transmitted from the cytosolic to the transmembrane (TM) domain in HCN4. We further discuss how detailed structural knowledge prompted the development of pharmacological/genetic tools for the control of cAMP regulation in these channels.</p>