Proteins in Motion

Some membrane receptors undergo conformational changes after binding their ligand, generating a signal transduction cascade that results in a change in gene expression. But how the motion of proteins is translated into altered signaling is not known. In their Perspective, [Gerstein and Chothia][1] describe how transmembrane helices in a bacterial membrane receptor slide over each other in a piston-like motion ([ Ottemann et al .][2]). They discuss how these results fit with current models of transmembrane conformational changes and signaling and whether these findings are likely to be applicable to other types of transmembrane proteins. [1]: http://www.sciencemag.org/cgi/content/full/285/5434/1682 [2]: http://www.sciencemag.org/cgi/content/short/285/5434/1751