title: Gating of thermally activated channels.
abstract: A class of ion channels that belongs to the transient receptor potential (TRP) superfamily and is present in specialized neurons that project to the skin has evolved as temperature detectors. These channels are classified into subfamilies, namely canonical (TRPC), melastatin (TRPM), ankyrin (TRPA), and vanilloid (TRPV). Some of these channels are activated by heat (TRPM2/4/5, TRPV1-4), while others by cold (TRPA1, TRPC5, and TRPM8). The general structure of these channels is closely related to that of the voltage-dependent K(+) channels, with their subunits containing six transmembrane segments that form tetramers. Thermal TRP channels are polymodal receptors. That is, they can be activated by temperature, voltage, pH, lipids, and agonists. The high temperature sensitivity in these thermal TRP channels is due to a large enthalpy change (∼100 kcal/mol), which is about five times the enthalpy change in voltage-dependent gating. The characterization of the macroscopic currents and single-channel analysis demonstrated that gating by temperature is complex and best described by branched or allosteric models containing several closed and open states. The identification of molecular determinants of temperature sensitivity in TRPV1, TRPA1, and TRPV3 strongly suggest that thermal sensitivity arises from a specific protein domain.
authors.affiliation: Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
authors.forename: David
authors.initials: D
authors.lastname: Baez
authors.affiliation: Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Centre for Plant Biotechnology and Genomics, Universidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid), Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Raddatz
authors.affiliation: Laboratorio de Canales Iónicos, Departamento de Biofísica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Ferreira
authors.affiliation: Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Gonzalez
authors.affiliation: Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
authors.forename: Ramon
authors.initials: R
authors.lastname: Latorre
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D015640:Ion Channel Gating; D007700:Kinetics; D008969:Molecular Sequence Data; D013816:Thermodynamics; D013697:Thermosensing; D050051:Transient Receptor Potential Channels / Q000737:chemistry / Q000378:metabolism*
chemical_list: D050051:Transient Receptor Potential Channels
keywords: Gating kinetic models; TRP channels; Thermal sensors; Thermodynamics