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Cover Image
Cover Image
Close ModalCover picture: Structures of a GIRK2 channel following molecular dynamics simulations show a closed state for the wild-type channel and a hypothetical open state for a mutant K200Y (KY) channel. Cross-sectional views (right) highlight the transmembrane gate (green) in the pore and PIP2. The authors provide evidence that the KY mutation in the PIP2-binding pocket leads to channel activation (see Research Article by Lacin et al., 799–811).
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Editorial
The Junior Faculty Networking Cohort: Filling a gap in support for our community
JGP, in partnership with the Society of General Physiologists, announces a new networking and mentoring program for junior faculty.
Research News
Different strokes for different synaptotagmins
JGP study shows how synaptotagmins 1 and 7 affect chromaffin cell granule fusion.
Commentary
Using fluorescence to understand β subunit–NaV channel interactions
Barro-Soria et al. highlight work that reveals how β1 and β3 subunits modulate NaV1.5 channel function.
Article
Synaptotagmin isoforms confer distinct activation kinetics and dynamics to chromaffin cell granules
Chromaffin cells release transmitters from populations of granules to which synaptotagmin-1 and synaptotagmin-7 are selectively sorted. Rao et al. characterize the functional properties of these granules and show that synaptotagmin-7 confers fast kinetics and high efficacy to the exocytotic event.
cAMP-dependent regulation of IKs single-channel kinetics
IKs channels are important for repolarization of cardiac action potentials during stress, but the mechanism has not been described microscopically. Thompson et al. show that cAMP facilitates voltage sensor activation in single channels, causing fewer silent sweeps, reduced first latency to opening, and occupancy of higher-subconductance states in open channels.
Dynamic role of the tether helix in PIP2-dependent gating of a G protein–gated potassium channel
G protein–gated inwardly rectifying potassium (GIRK) channels are activated by the phospholipid phosphatidylinositol 4,5 bisphosphate (PIP2). Using functional and computational experiments, Lacin et al. reveal that PIP2 interacts with the tether helix of the neuronal GIRK channel in a dynamic way.
Mechanisms of noncovalent β subunit regulation of NaV channel gating
Voltage-gated NaV channels are modulated by two different noncovalent accessory subunits: β1 and β3. Zhu et al. present data showing that β1 and β3 cause distinct effects on channel gating because they interact with NaV channels at different locations. β3 regulates the voltage sensor in domain III, whereas β1 regulates the one in domain IV.
