title: Activity and Ca²⁺ regulate the mobility of TRPV1 channels in the plasma membrane of sensory neurons.
abstract: TRPV1 channels are gated by a variety of thermal, chemical, and mechanical stimuli. We used optical recording of Ca(2+) influx through TRPV1 to measure activity and mobility of single TRPV1 molecules in isolated dorsal root ganglion neurons and cell lines. The opening of single TRPV1 channels produced sparklets, representing localized regions of elevated Ca(2+). Unlike sparklets reported for L-type Ca(2+) channels, TRPV4 channels, and AchR channels, TRPV1 channels diffused laterally in the plasma membrane as they gated. Mobility was highly variable from channel-to-channel and, to a smaller extent, from cell to cell. Most surprisingly, we found that mobility decreased upon channel activation by capsaicin, but only in the presence of extracellular Ca(2+). We propose that decreased mobility of open TRPV1 could act as a diffusion trap to concentrate channels in cell regions with high activity.
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, United States.
authors.forename: Eric N
authors.initials: EN
authors.lastname: Senning
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, United States.
authors.forename: Sharona E
authors.initials: SE
authors.lastname: Gordon
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002211:Capsaicin / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D005453:Fluorescence; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D038761:Photobleaching; D021381:Protein Transport / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection
chemical_list: D011993:Recombinant Fusion Proteins; D050916:TRPV Cation Channels; D049452:Green Fluorescent Proteins; D002211:Capsaicin; D002118:Calcium
keywords: TRPV1; calcium signaling; cell biology; diffusion; gating; human; mobility; mouse; neuroscience; rat; sparklet