Gramicidin A channels switch between stretch activation and stretch inactivation depending on bilayer thickness.
The patch clamp-liposome technique was used to examine the stretch sensitivity of a model membrane ion channel, gramicidin A, in membrane patches of different bilayer thickness. We found that small changes in phospholipid acyl chain length (i.e., PC-20 to PC-18) can switch gramicidin A from a stretch-activated to a stretch-inactivated channel. The demonstration that subnanometer changes in bilayer thickness can reverse the response polarity of a model channel has implications for other signaling proteins that may experience local changes in bilayer thickness as a consequence of dynamic targeting to lipid microdomains, electrocompression, or chemical modification of the bilayer.
Martinac
Boris
B
Department of Pharmacology, University of Western Australia, Crawley, West Australia 6009.
Hamill
Owen P
OP
D006096:Gramicidin / Q000737:chemistry* / Q000378:metabolism; D007473:Ion Channels / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D018408:Patch-Clamp Techniques
D007473:Ion Channels; D008051:Lipid Bilayers; D006096:Gramicidin