Newest Articles
Mechanisms of Na+ channel regulation by β1 and β3Voltage-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.
PIP2-dependent gating of GIRK channelsG 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.
Isoform-specific properties of synaptotagminChromaffin 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 effects on IKs gatingIKs 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.
Elevated cAMP improves rod signal-to-noise ratioVertebrate photoreceptors need to distinguish light signals from background noise to convey visual information to downstream bipolar cells. By affecting both signal and noise, Astakhova et al. find that increases in intracellular cAMP can improve the signal-to-noise ratio by twofold.
Na/K pump inactivation and restricted Na spacesThe Na/K pump exports cytoplasmic Na ions while importing K ions, and its activity is thought to be affected by restricted intracellular Na diffusion in cardiac myocytes. Lu and Hilgemann find instead that the pump can enter an inactivated state and that inactivation can be relieved by cytoplasmic Na.
ICC Ca2+ transient clusteringElectrical slow waves in the small intestine are generated by pacemaker cells called interstitial cells of Cajal. Drumm et al. record clusters of Ca2+ transients in these cells that are entrained by voltage-dependent Ca2+ entry and which define the duration of the electrical slow waves.
JGP, in partnership with the Society of General Physiologists, announces a new networking and mentoring program for junior faculty.