The mechanosensitive nature of TRPV channels.
Transient receptor potential vanilloid (TRPV) channels are widely expressed in both sensory and nonsensory cells. Whereas the channels display a broad diversity to activation by chemical and physical stimuli, activation by mechanical stimuli is common to many members of this group in both lower and higher organisms. Genetic screening in Caenorhabditis elegans has demonstrated an essential role for two TRPV channels in sensory neurons. OSM-9 and OCR-2, for example, are essential for both osmosensory and mechanosensory (nose-touch) behaviors. Likewise, two Drosophila TRPV channels, NAN and IAV, have been shown to be critical for hearing by the mechanosensitive chordotonal organs located in the fly's antennae. The mechanosensitive nature of the channels appears to be conserved in higher organisms for some TRPV channels. Two vertebrate channels, TRPV2 and TRPV4, are sensitive to hypotonic cell swelling, shear stress/fluid flow (TRPV4), and membrane stretch (TRPV2). In the osmosensing neurons of the hypothalamus (circumventricular organs), TRPV4 appears to function as an osmoreceptor, or part of an osmoreceptor complex, in control of vasopressin release, whereas in inner ear hair cells and vascular baroreceptors a mechanosensory role is suggestive, but not demonstrated. Finally, in many nonsensory cells expressing TRPV4, such as vascular endothelial cells and renal tubular epithelial cells, the channel exhibits well-developed local mechanosensory transduction processes where both cell swelling and shear stress/fluid flow lead to channel activation. Hence, many TRPV channels, or combinations of TRPV channels, display a mechanosensitive nature that underlies multiple mechanosensitive processes from worms to mammals.
O'Neil
Roger G
RG
Department of Integrative Biology and Pharmacology, Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA. roger.g.oneil@uth.tmc.edu
Heller
Stefan
S
D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000502:physiology; D015220:Calcium Channels / Q000502:physiology; D029721:Drosophila Proteins / Q000502:physiology; D006198:Hair Cells, Auditory / Q000502:physiology; D006309:Hearing / Q000502:physiology; D006801:Humans; D007473:Ion Channels / Q000502:physiology; D008465:Mechanoreceptors / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000502:physiology; D009997:Osmotic Pressure; D011311:Pressoreceptors / Q000502:physiology; D013314:Stress, Mechanical; D050916:TRPV Cation Channels / Q000502:physiology*; D014110:Touch / Q000502:physiology; D050051:Transient Receptor Potential Channels / Q000502:physiology; D029961:Zebrafish Proteins / Q000502:physiology
D029742:Caenorhabditis elegans Proteins; D015220:Calcium Channels; D029721:Drosophila Proteins; C494780:IAV protein, Drosophila; D007473:Ion Channels; C476010:Nan protein, Drosophila; D009419:Nerve Tissue Proteins; C464589:OCR-1 protein, C elegans; C108820:OSM-9 protein, C elegans; D050916:TRPV Cation Channels; D050051:Transient Receptor Potential Channels; C486576:Trpv4 protein, mouse; D029961:Zebrafish Proteins; C475465:trpn1 protein, zebrafish