Gaete et al. have designed a methodology that allows quantitative analysis of the permeation of ions and molecules through connexin and CALHM1 large-pore channels. Both channels display saturable transport of molecules that could be described by Michaelis-Menten kinetics with apparent Km and Vmax.

Prieto et al. describe how ultrasound can either inhibit or potentiate action potential firing in hippocampal pyramidal neurons and demonstrate that these effects can be explained by increased potassium conductance.

The present work shows that SR Ca2+ load and RYR2 Ca2+ sensitivity are major determinants of Ca2+ release restitution (CRR) after each heartbeat. Mathematical modeling led us to speculate that the velocity of SR Ca2+ refilling might regulate CRR independently of SR Ca2+ content.

The voltage-gated proton channel (HV1) resembles the voltage sensors of other channels, but its movement during channel opening remains controversial. Cherny et al. establish open and closed gating configurations of HV1 by analyzing the interactions of Zn2+ with an introduced histidine residue.

K+ binding to mammalian glutamate transporters is essential for the import and release of glutamate into cells. Using MD simulations and site-directed mutagenesis, Wang et al. identify two K+ binding sites in the transporter EAAC1, one of which appears to catalyze the relocation step of the transport cycle.

Stress increases the permeability of the mitochondrial inner membrane by activating permeability transition pores (PTPs), likely composed of ATP synthase or the adenine nucleotide translocator. By measuring water flux during calcium-activated mitochondrial swelling, Neginskaya et al. estimate that if these proteins are involved in PTP, only a small fraction becomes transformed into the pore on a single mitochondrion.

Mice lacking calsequestrin-1 have reduced levels of releasable Ca2+ in the sarcoplasmic reticulum of their skeletal muscles. Michelucci et al. reveal that this is compensated by constitutive assembly of STIM1 and Orai1 into Ca2+ entry units, promoting both constitutive and store-operated Ca2+ entry.