A yeast genetic screen reveals a critical role for the pore helix domain in TRP channel gating.
TRP cation channels function as cellular sensors in uni- and multicellular eukaryotes. Despite intensive study, the mechanisms of TRP channel activation by chemical or physical stimuli remain poorly understood. To identify amino acid residues crucial for TRP channel gating, we developed an unbiased, high-throughput genetic screen in yeast that uncovered rare, constitutively active mutants of the capsaicin receptor, TRPV1. We show that mutations within the pore helix domain dramatically increase basal channel activity and responsiveness to chemical and thermal stimuli. Mutation of corresponding residues within two related TRPV channels leads to comparable effects on their activation properties. Our data suggest that conformational changes in the outer pore region are critical for determining the balance between open and closed states, providing evidence for a general role for this domain in TRP channel activation.
Myers
Benjamin R
BR
Department of Physiology, University of California, San Francisco, 600 16th Street, San Francisco, CA 94143-2140, USA.
Bohlen
Christopher J
CJ
Julius
David
D
D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D002460:Cell Line; D005820:Genetic Testing / Q000379:methods*; D006358:Hot Temperature; D006801:Humans; D015640:Ion Channel Gating / Q000502:physiology*; D007668:Kidney / Q000166:cytology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D016296:Mutagenesis / Q000502:physiology; D009865:Oocytes / Q000502:physiology; D018408:Patch-Clamp Techniques; D017433:Protein Structure, Secondary; D051381:Rats; D012441:Saccharomyces cerevisiae; D013268:Stimulation, Chemical; D013329:Structure-Activity Relationship; D050916:TRPV Cation Channels / Q000737:chemistry* / Q000235:genetics* / Q000502:physiology; D014982:Xenopus laevis
D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat; D002211:Capsaicin