Secondary active transport mechanisms often depict a limited number of states and transitions, although recent research suggests that alternative “leak” pathways are not always minor. Hussey et al. numerically simulate a fully unrestricted model for the bacterial transporter EmrE and demonstrate that highly efficient transport can be achieved despite the existence of multiple leak pathways.

CRAC channels contain a cluster of positively charged residues in the inner pore whose function is not understood. Here, we show that these positive charges promote pore opening by enhancing hydration of the hydrophobic gate located at the outer end of the pore.

Using single-channel recordings and single-molecule FRET, Carrillo et al. show that resensitization of α-amino-5-methyl-3-hydroxy-4-isoxazole propionate receptors by the regulatory protein γ8 is characterized by transitions to high conductance levels associated with tighter conformational coupling similar to those seen in the presence of cyclothiazide.

This paper presents the crystal structure of a forced open inward rectifier Kir2.2 channel. Molecular dynamics reveals the details of ion permeation through the open channel.

Ma et al. studied the 3-D arrangement of thick filaments in skeletal muscle by x-ray diffraction and electron microscopy and found a correlation between thick filament lattice type (simple or superlattice) and fiber type (fast/slow). This suggests that lattice organization contributes to muscle functional properties.

Cochlear amplification is mediated by the outer hair cell of the organ of Corti. Santos-Sacchi et al. reveal that the cell possesses a voltage-dependent motile frequency response that differs from that of its voltage sensor/effector, the electromotile protein prestin, implying variable coupling between the two.

This paper describes the dynamics of proteins and lipids during exocytosis of MMP-9 from cancer cells in real time using fluorescence microscopy. Stephens et al. find that core exocytic proteins, accessory proteins, and lipids are involved at sites of secretory vesicle fusion.