Issues

JGP study suggests that, by altering mechanosensitive signaling pathways, replating stem cell-derived cardiomyocytes changes myosin expression and contractile function.

Computational study suggests that π-bulges play an integral role in the gating mechanisms of Cav channels, governing the binding of enantiomeric DHP.

Osten et al. describe rapid changes in myosin heavy chain isoform expression, contractile function, and calcium transients after enzymatic detachment and replating of human stem cell–derived cardiomyocytes (CMs). These changes may alter mechanosensation and need to be considered when replating CMs in the context of functional measurements.

Hu et al. demonstrate that, independent of other countercurrents, TRIC-A and TRIC-B differentially modulate RyR2 gating. Results also suggest that TRIC-A and TRIC-B are permeable to both K⁺ and Cl⁻, thus enabling them to provide adaptable countercurrents for many cell types.

This study examined how structural microdomains comprising the Ca²⁺-activated Cl⁻ channel encoded by Tmem16a or Anoctamin-1 (ANO1) interact with voltage-gated Ca²⁺ channel Ca_V1.2 in the plasma membrane and how Ca²⁺ release from IP₃ receptors in the sarcoplasmic reticulum drive intracellular Ca²⁺ waves and force production of pulmonary artery smooth muscle cells in response to the vasoconstrictor agonist serotonin.

The Fitzsimons lab examines the activation dependence of contractile kinetics in mouse and swine hearts. Their findings demonstrate that the cooperative mechanisms underlying contraction differ in the hearts of small and large mammals and yield insights into normal heart function.

We show that isoproterenol applied to rat ventricular myocytes produced symmetrical increases in the size of ryanodine receptor clusters, a decrease in fragmentation, and the coalescence of smaller clusters. Additionally, receptors were found in irregularly arranged arrays resembling those seen by electron tomography.

KCNMA1 regulates circadian rhythm in animals, and mutations in this potassium channel are associated with human neuromotor disease. Dinsdale et al. evaluated circadian clock function in three mouse models harboring KCNMA1 mutations associated with human channelopathies and found clock-controlled behavioral deficits without primary rhythm ablation.

Wells et al. show that a transmural conduction gradient that exists in rat ventricular slices is abolished in settings of increased pericardial adiposity, with slowed epicardial conduction strongly correlating with an increase in cardiomyocyte lipid content.

Computational models based on different cryo-EM structures of ligand-bound calcium and sodium channels suggest that dihydropyridine antagonists stabilize entirely α-helical conformation of the pore-lining helix S6_IV, whereas agonists promote channel opening by stabilizing π-bulged helix S6_IV.