Recent studies using diverse techniques have led to radically different interpretations of the structure and molecular motion of the voltage sensor in voltage-gated ion channels.
This review highlights the conflicting interpretations of voltage sensor mechanisms in ion channels and discusses potential causes for these discrepancies to guide future research.
Neurons transmit information through electrical signals generated by voltage-gated ion channels. These channels consist of a large superfamily of proteins that form channels selective for potassium, sodium, or calcium ions. In this review we focus on the molecular mechanisms by which these channels convert changes in membrane voltage into the opening and closing of "gates" that turn ion conductance on and off. An explosion of new studies in the last year, including the first X-ray crystal structure of a mammalian voltage-gated potassium channel, has led to radically different interpretations of the structure and molecular motion of the voltage sensor. The interpretations are as distinct as the techniques employed for the studies: crystallography, fluorescence, accessibility analysis, and electrophysiology. We discuss the likely causes of the discrepant results in an attempt to identify the missing information that will help resolve the controversy and reveal the mechanism by which a voltage sensor controls the channel's gates.
Tombola et al. (2006) conducted a review in Voltage-gated ion channels. Recent studies using diverse techniques have led to radically different interpretations of the structure and molecular motion of the voltage sensor in voltage-gated ion channels.