An Nramp transition metal transporter performs metal uniport, proton uniport, and proton–metal cotransport. Transmembrane voltage and pH gradients govern the rates of these processes, largely through a conserved salt-bridge network in the transmembrane scaffold of the transporter’s LeuT fold.

This paper describes the first extensive study of voltage-clamp recordings from WT and mutant mouse cone photoreceptors made from dark-adapted retinas without fluorescent markers. Cones can continue to adapt rapidly in bright light, even without known mechanisms of transduction modulation.

The active force of mammalian skeletal muscle is reduced at low temperatures. Caremani et al. reveal that this is due to the rise of a population of myosin motors captured in a refractory state insensitive to muscle activation.