title: Voltage- and temperature-dependent activation of TRPV3 channels is potentiated by receptor-mediated PI(4,5)P2 hydrolysis.
abstract: TRPV3 is a thermosensitive channel that is robustly expressed in skin keratinocytes and activated by innocuous thermal heating, membrane depolarization, and chemical agonists such as 2-aminoethyoxy diphenylborinate, carvacrol, and camphor. TRPV3 modulates sensory thermotransduction, hair growth, and susceptibility to dermatitis in rodents, but the molecular mechanisms responsible for controlling TRPV3 channel activity in keratinocytes remain elusive. We show here that receptor-mediated breakdown of the membrane lipid phosphatidylinositol (4,5) bisphosphate (PI(4,5)P(2)) regulates the activity of both native TRPV3 channels in primary human skin keratinocytes and expressed TRPV3 in a HEK-293-derived cell line stably expressing muscarinic M(1)-type acetylcholine receptors. Stimulation of PI(4,5)P(2) hydrolysis or pharmacological inhibition of PI 4 kinase to block PI(4,5)P(2) synthesis potentiates TRPV3 currents by causing a negative shift in the voltage dependence of channel opening, increasing the proportion of voltage-independent current and causing thermal activation to occur at cooler temperatures. The activity of single TRPV3 channels in excised patches is potentiated by PI(4,5)P(2) depletion and selectively decreased by PI(4,5)P(2) compared with related phosphatidylinositol phosphates. Neutralizing mutations of basic residues in the TRP domain abrogate the effect of PI(4,5)P(2) on channel function, suggesting that PI(4,5)P(2) directly interacts with a specific protein motif to reduce TRPV3 channel open probability. PI(4,5)P(2)-dependent modulation of TRPV3 activity represents an attractive mechanism for acute regulation of keratinocyte signaling cascades that control cell proliferation and the release of autocrine and paracrine factors.
authors.affiliation: Department of Cell Physiology, Ruhr University Bochum, 44801 Bochum, Germany.
authors.forename: Julia F
authors.initials: JF
authors.lastname: Doerner
authors.forename: Hanns
authors.initials: H
authors.lastname: Hatt
authors.forename: I Scott
authors.initials: IS
authors.lastname: Ramsey
mesh_terms: D019870:1-Phosphatidylinositol 4-Kinase / Q000378:metabolism; D020816:Amino Acid Motifs; D001665:Binding Sites; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D006868:Hydrolysis; D015640:Ion Channel Gating / Q000187:drug effects; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008564:Membrane Potentials; D009154:Mutation; D018408:Patch-Clamp Techniques; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D054799:Phospholipase C beta / Q000378:metabolism; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic / Q000235:genetics / Q000378:metabolism; D011983:Receptors, Purinergic / Q000378:metabolism; D015290:Second Messenger Systems / Q000187:drug effects; D050916:TRPV Cation Channels / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D014162:Transfection
chemical_list: C086088:CHRM1 protein, human; D019269:Phosphatidylinositol 4,5-Diphosphate; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic; D011983:Receptors, Purinergic; D050916:TRPV Cation Channels; C459445:TRPV3 protein, human; D019870:1-Phosphatidylinositol 4-Kinase; D054799:Phospholipase C beta; D043802:GTP-Binding Protein alpha Subunits, Gq-G11