Issues

A new JGP study shows that the gating ring helps the voltage-sensing domain open the BK channel’s pore.

Moss et al. highlight why high-frequency bursts at the onset of tetany increase force development in fast-twitch skeletal muscle fibers.

Chang et al. review fusion pore structure and dynamics and discuss the implications for hormone and neurotransmitter release

High-frequency paired stimuli used to initiate a tetanus result in increased force and rate of force development in skeletal muscle. Bakker et al. investigate this mechanism and find that doublet stimulation increases the amount of Ca²⁺ bound to troponin C, resulting in rapid force development.

Visual stimuli of different frequencies are encoded in the retina using transient and sustained responses. Zhao et al. describe the different strategies that are used by four types of retinal ganglion cells to shape photoresponse kinetics.

Gating of the CFTR channel is coupled to ATP hydrolysis such that two open states can be identified under certain conditions. Zhang and Hwang find that pore-lining mutations differentially affect the permeation properties of these open states and suggest that the internal vestibule expands upon ATP hydrolysis.

Both cellular depolarization and intracellular Ca²⁺ can gate open large conductance Ca²⁺-activated K⁺ channels. Zhang et al. show that the intracellular gating ring, which forms the Ca²⁺-sensing machinery of the channel, is also required for activated voltage sensors to effectively gate open the pore.

Hsu et al. probe voltage-gated Na⁺ channels that are inactivation deficient with voltage-clamp fluorometry. They find that in the time domain of an action potential, the voltage-sensing domain (VSD) of domain IV regulates fast inactivation onset while the domain III VSD determines its recovery.