Issues

JGP study reveals that, although they are present at low levels and only generate small currents in the sinoatrial node, Kv1.1 channels have a significant impact on cardiac pacemaking.

This Commentary discusses the implications of a recent JGP study demonstrating an AI model to quantify glycogen granules.

RRAD is a constituent of the L-type calcium channel heteromultimeric complex. RRAD contributes to calcium channel modulation. Elmore, Ahern et al. show that the RRAD C-terminus confers membrane association concomitantly with the regulation of I_Ca,L modulation and in vivo heart function.

Si et al. use electrophysiology to show that genetic or pharmacological ablation of Kv1.1 K⁺ channel subunits reduces the firing rate of the heart’s sinoatrial node in mice. They attribute this decrease to impaired outward K⁺ currents resulting in prolonged action potentials. These findings identify Kv1.1 as a novel regulator of cardiac pacemaking.

Artificial neural networks developed to quantify glycogen granules in EM images of human muscle find granular content that varies with cell region and is threefold lower than normal in patients susceptible to malignant hyperthermia, a condition with chronically elevated cytoplasmic [Ca²⁺].