Newest Articles
State-dependent binding of cAMP to spHCN channelsMammalian hyperpolarization-activated cyclic-nucleotide–modulated (HCN) channels bind cAMP preferably in the open state. Using sea urchin HCN channels, Idikuda et al. reveal less cAMP binding to the closed state and further reduced binding to the inactivated state and thus demonstrate intricate communication between the gate and ligand-binding domain.
RyR2 modulation by phosphorylation at S2030Phosphorylation is thought to play a role in modulation of the ryanodine receptor 2 channel. Using a S2030A knock-in mouse model, Potenza et al. reveal that phosphorylation of RyR2-S2030 mediates channel regulation during the β-adrenergic response.
Destabilization of relaxation in hERG channelsThe human ether-à-go-go–related gene (hERG) encodes a delayed rectifier K+ channel with slow deactivation gating. Shi et al. find that acidic residues on S3 contribute to slow deactivation kinetics by stabilizing the relaxed state of the voltage sensor, which can be mitigated by extracellular protons.
Control of Cx26 gating by cytosolic domainsThe N14K mutation in the N-terminal domain of connexin26 produces gain-of-function hemichannels. Valdez Capuccino et al. reveal that the mutation disrupts intersubunit interactions between the N terminus and the second transmembrane domain–cytoplasmic loop transition.
Titin compliance reduces length-dependent troponin regulationIncreases in sarcomere length cause enhanced force generation in cardiomyocytes by an unknown mechanism. Li et al. reveal that titin-based passive tension contributes to length-dependent activation of myofilaments and that tightly bound myosin–actin cross-bridges are associated with this effect.
RLC phosphorylation and β-myosin heavy chain functionContraction of cardiac muscle is regulated by sarcomere length and proteins that comprise the sarcomeric filaments. Breithaupt et al. find that phosphorylation of myosin regulatory light chain augments length-dependent activation of contraction when β-cardiac myosin heavy chain predominates.
The structure of the cardiac thick filament in diastoleThick filament mechanosensing has been proposed as the mechanism by which myosin motors in cardiac muscle become available to bind actin. Accordingly, Caremani et al., using x-ray diffraction from intact rat trabeculae, show that myosin motors fully return to their OFF state during diastole independently of inotropic interventions.
Current Issue
December 3, 2018
Volume 150, No. 12
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Reviews & Opinions
- Visualization of expanding fusion pores in secretory cells
Abbineni et al. examine recent imaging work on fusion pores and discuss the dynamics of PI-4,5-P2 accumulation on granule membranes.
- Influences: Russian training
Sobolevsky reflects on his unique scientific upbringing in Russia.
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Navarro et al discuss new work using the gating-modifier toxin GxTx to investigate the molecular mechanism of Kv2.1 channel gating.