Phosphoinositides, rare membrane lipids, mediate powerful second messenger signals to ion channels, endocytosis, and exocytosis, and specify organelle identity. Jensen et al. summarize 20 yr of biophysical research whose key message is that pools of phosphoinositides turn over remarkably quickly to regulate rapid physiological responses.
A strategy for determining the equilibrium constants for heteromeric ion channels in a complex model
Benndorf et al. present a strategy to analyze the functionality of heteromeric ligand-gated ion channels by combining subunit concatenation, mutagenesis, and extensive global fit strategies with intimately coupled Markov models.
Marquis and Sack show that the use-dependent inhibition of Kv2.1 by RY785 is consistent with gated access to a cavity within the channel that traps RY785. While voltage activation is required for access to the blocking site, channel opening itself is not required for access.
Godellas and Grosman revisit the use of ligand-binding assays to study pentameric ligand-gated ion channels (pLGICs). They show that ligand-binding affinity is unaffected by binding-site occupancy and that changes to the transmembrane domain are unlikely to affect binding to the extracellular domain.