Photoswitchable affinity labels for optical regulation of native potassium channels

BIOL 146

Matthew R. Banghart, matt_b@berkeley.edu1, Doris L. Fortin2, Richard H. Kramer2, and Dirk Trauner, trauner@berkeley.edu1. (1) Department of Chemistry, University of California, Berkeley, Latimer Hall, Berkeley, CA 94720, (2) Department of Molecular and Cell Biology, University of California, Berkeley, 129 Valley Life Sciences Addition, Berkeley, CA 94720
Photosensitive ion channels, which afford remote control of electrical activity in neurons, are emerging tools in neurobiology. To function in cells, current systems require gene transfection. We now report the development of photoswitchable affinity labels for optical regulation of native potassium channels in neurons. This approach relies on the presence of nucleophilic side chains at a specific distance from the binding site of tetraethylammonium, a pore-blocker. To target these residues, we screened a series of photoswitchable ligands composed of an azobenzene, a pore-blocker, and various electrophiles for the ability to photoregulate wild-type Shaker potassium channels. Each electrophile tested renders Shaker channels photosensitive when expressed in Xenopus oocytes. These reagents also react with native potassium channels in neurons, affording optical control of electrical activity without the need for gene transfection. The site(s) of bioconjugation and the ability of different potassium channel subtypes to undergo photoregulation with these reagents were investigated.
 

Chemistry and Metabolism
4:30 PM-6:30 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster

Division of Biological Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006