title: Identification of a binding motif in the S5 helix that confers cholesterol sensitivity to the TRPV1 ion channel.
abstract: The TRPV1 ion channel serves as an integrator of noxious stimuli with its activation linked to pain and neurogenic inflammation. Cholesterol, a major component of cell membranes, modifies the function of several types of ion channels. Here, using measurements of capsaicin-activated currents in excised patches from TRPV1-expressing HEK cells, we show that enrichment with cholesterol, but not its diastereoisomer epicholesterol, markedly decreased wild-type rat TRPV1 currents. Substitutions in the S5 helix, rTRPV1-R579D, and rTRPV1-F582Q, decreased this cholesterol response and rTRPV1-L585I was insensitive to cholesterol addition. Two human TRPV1 variants, with different amino acids at position 585, had different responses to cholesterol with hTRPV1-Ile(585) being insensitive to this molecule. However, hTRPV1-I585L was inhibited by cholesterol addition similar to rTRPV1 with the same S5 sequence. In the absence of capsaicin, cholesterol enrichment also inhibited TRPV1 currents induced by elevated temperature and voltage. These data suggest that there is a cholesterol-binding site in TRPV1 and that the functions of TRPV1 depend on the genetic variant and membrane cholesterol content.
authors.affiliation: Departamento de Neurodesarrollo y Fisiología, División Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, D.F. 04510, México.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Picazo-Juárez
authors.forename: Silvina
authors.initials: S
authors.lastname: Romero-Suárez
authors.forename: Andrés
authors.initials: A
authors.lastname: Nieto-Posadas
authors.forename: Itzel
authors.initials: I
authors.lastname: Llorente
authors.forename: Andrés
authors.initials: A
authors.lastname: Jara-Oseguera
authors.forename: Margaret
authors.initials: M
authors.lastname: Briggs
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: McIntosh
authors.forename: Sidney A
authors.initials: SA
authors.lastname: Simon
authors.forename: Ernesto
authors.initials: E
authors.lastname: Ladrón-de-Guevara
authors.forename: León D
authors.initials: LD
authors.lastname: Islas
authors.forename: Tamara
authors.initials: T
authors.lastname: Rosenbaum
mesh_terms: D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D002211:Capsaicin / Q000494:pharmacology; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D002784:Cholesterol / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D020125:Mutation, Missense; D051381:Rats; D018689:Sensory System Agents / Q000494:pharmacology; D013045:Species Specificity; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D018689:Sensory System Agents; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; C493922:Trpv1 protein, rat; D002784:Cholesterol; D002211:Capsaicin