title: Stimulus-specific modulation of the cation channel TRPV4 by PACSIN 3.
abstract: TRPV4, a member of the vanilloid subfamily of the transient receptor potential (TRP) channels, is activated by a variety of stimuli, including cell swelling, moderate heat, and chemical compounds such as synthetic 4alpha-phorbol esters. TRPV4 displays a widespread expression in various cells and tissues and has been implicated in diverse physiological processes, including osmotic homeostasis, thermo- and mechanosensation, vasorelaxation, tuning of neuronal excitability, and bladder voiding. The mechanisms that regulate TRPV4 in these different physiological settings are currently poorly understood. We have recently shown that the relative amount of TRPV4 in the plasma membrane is enhanced by interaction with the SH3 domain of PACSIN 3, a member of the PACSIN family of proteins involved in synaptic vesicular membrane trafficking and endocytosis. Here we demonstrate that PACSIN 3 strongly inhibits the basal activity of TRPV4 and its activation by cell swelling and heat, while leaving channel gating induced by the synthetic ligand 4alpha-phorbol 12,13-didecanoate unaffected. A single proline mutation in the SH3 domain of PACSIN 3 abolishes its inhibitory effect on TRPV4, indicating that PACSIN 3 must bind to the channel to modulate its function. In line herewith, mutations at specific proline residues in the N terminus of TRPV4 abolish binding of PACSIN 3 and render the channel insensitive to PACSIN 3-induced inhibition. Taken together, these data suggest that PACSIN 3 acts as an auxiliary protein of TRPV4 channel that not only affects the channel's subcellular localization but also modulates its function in a stimulus-specific manner.
authors.affiliation: Department of Physiology, Katholieke Universiteit Leuven, Campus Gasthuisberg, O&N 1, Herestraat 49 Bus 802, Leuven, Belgium. dieter.dhoedt@med.kuleuven.be
authors.forename: Dieter
authors.initials: D
authors.lastname: D'hoedt
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Owsianik
authors.forename: Jean
authors.initials: J
authors.lastname: Prenen
authors.forename: Math Pham
authors.initials: MP
authors.lastname: Cuajungco
authors.forename: Christian
authors.initials: C
authors.lastname: Grimm
authors.forename: Stefan
authors.initials: S
authors.lastname: Heller
authors.forename: Thomas
authors.initials: T
authors.lastname: Voets
authors.forename: Bernd
authors.initials: B
authors.lastname: Nilius
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D040542:Mechanotransduction, Cellular / Q000187:drug effects / Q000502:physiology; D051379:Mice; D009474:Neurons / Q000378:metabolism; D009928:Organ Specificity / Q000502:physiology; D010703:Phorbol Esters / Q000494:pharmacology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002273:Carcinogens; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C421762:PACSIN3 protein, human; C486019:Pacsin3 protein, mouse; D010703:Phorbol Esters; D010750:Phosphoproteins; D050916:TRPV Cation Channels; C416986:TRPV4 protein, human; C486576:Trpv4 protein, mouse