title: Intact microtubules preserve transient receptor potential vanilloid 1 (TRPV1) functionality through receptor binding.
abstract: The transient receptor potential cation channel subfamily V member 1 (TRPV1) is a protein currently under scrutiny as a pharmacological target for pain management therapies. Recently, the role of TRPV1-microtubule interaction in transducing nociception stimuli to cells by cytoskeletal rearrangement was proposed. In this work, we investigate TRPV1-microtubule interaction in living cells under the resting or activated state of TRPV1, as well as in presence of structurally intact or depolymerized cytoskeletal microtubules. We combined a toolbox of high resolution/high sensitivity fluorescence imaging techniques (such as FRET, correlation spectroscopy, and fluorescence anisotropy) to monitor TRPV1 aggregation status, membrane mobility, and interaction with microtubules. We found that TRPV1 is a dimeric membrane protein characterized by two populations with different diffusion properties in basal condition. After stimulation with resiniferatoxin, TRPV1 dimers tetramerize. The tetramers and the slower population of TRPV1 dimers bind dynamically to intact microtubules but not to tubulin dimers. Upon microtubule disassembly, the interaction with TRPV1 is lost thereby inducing receptor self-aggregation with partial loss of functionality. Intact microtubules play an essential role in maintaining TRPV1 functionality toward activation stimuli. This previously undisclosed property mirrors the recently reported role of TRPV1 in modulating microtubule assembly/disassembly and suggests the participation of these two players in a feedback cycle linking nociception and cytoskeletal remodeling.
authors.affiliation: National Enterprise for nanoScience and nanoTechnology (NEST), Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza S. Silvestro 12, 56127 Pisa, Italy. barbara.storti@sns.it
authors.forename: Barbara
authors.initials: B
authors.lastname: Storti
authors.forename: Ranieri
authors.initials: R
authors.lastname: Bizzarri
authors.forename: Francesco
authors.initials: F
authors.lastname: Cardarelli
authors.forename: Fabio
authors.initials: F
authors.lastname: Beltram
mesh_terms: D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D004224:Diterpenes / Q000494:pharmacology; D006801:Humans; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D059225:Nociception / Q000187:drug effects / Q000502:physiology*; D055503:Protein Multimerization / Q000187:drug effects / Q000502:physiology*; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D004224:Diterpenes; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; C024353:resiniferatoxin