Using a mathematical model, Stephenson tests the hypothesis that the characteristic response to Ca²⁺ of RyR channels is key not only for the Ca²⁺ release mechanism in cardiac muscle and other tissues, but also for the DHPR-dependent Ca²⁺ release in skeletal muscles.

Mott et al. evaluate two click-chemistry protein labeling tools based on genetic code expansion technology and circularly permutated Halotag, respectively, for their utility in TRPV1 cell surface expression studies.

Kooiker et al. investigate the mechanisms of a novel cardiac myosin inhibitor that depends on the presence of a myosin regulatory light chain (RLC-1). They show that RLC-1 destabilizes myosin interactions to inhibit force and accelerate kinetics in cardiac muscle.

The ω-grammotoxin-SIA peptide (GrTx-SIA) was originally found in tarantula venom and shown to inhibit voltage-gated Ca²⁺ channels. Here, Collaço et al. report that GrTx-SIA can also potently inhibit voltage-gated Na⁺ channel currents, with Na_V1.6 being the most susceptible subtype.

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.

Animal cells regulate their volume by actively pumping sodium and potassium ions, preventing the osmotic influx of water from bursting the cell. We have extended the pump-leak equations that are used to characterize such systems to include impermeant extracellular molecules, cation–chloride co-transporters, and the energetics of ion transport.

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.