Shake, rattle or roll?

摘要

Nerve transmission depends on voltage-gated ion-channel proteins, which in turn depend on the behaviour of a membrane domain called the voltage sensor. Therein lies the latest episode in a continuing story. The propagation of electrical signals in the nervous system endows animals with moment-to-moment overall coherence. Without it, worms could not wriggle, flies could not find fruit, and we could not read News and Views. Electrical impulses coursing down the nerve axon arise from a molecular minuet in which ion-channel proteins deliver charged particles, Na~+ and K~+, across the nerve membrane. These proteins possess a special property ― voltage dependence, not known in any other macromolecule ― that causes their activity to be controlled by the very voltage changes they generate. Voltage dependence arises from the transmembrane movement of charged ammo acids on the protein, con-comitant with opening of the ion-conduct-ing pore. The part of the protein containing these 'gating charges', the voltage sensor, is known, but the way it moves is highly contro-versial. Starace and Bezanilla' (page 548) now describe a remarkable property of the voltage sensor that sharpens our view of its transmembrane movement.