Salazar, H. et al. A single N-terminal cysteine in TRPV1 determines activation by pungent compounds from onion and garlic. Nat. Neurosci. 11, 255-261

Departamento de Biofísica, Instituto de Fisiología Celular, Circuito Exterior S/N, Ciudad Universitaria, Universidad Nacional Autónoma de México, México, D.F., 04510, Mexico.
Nature Neuroscience (Impact Factor: 16.1). 04/2008; 11(3):255-61. DOI: 10.1038/nn2056
Source: PubMed


Some members of the transient receptor potential (TRP) family of cation channels mediate sensory responses to irritant substances. Although it is well known that TRPA1 channels are activated by pungent compounds found in garlic, onion, mustard and cinnamon extracts, activation of TRPV1 by these extracts remains controversial. Here we establish that TRPV1 is activated by pungent extracts from onion and garlic, as well as by allicin, the active compound in these preparations, and participates together with TRPA1 in the pain-related behavior induced by this compound. We found that in TRPV1 these agents act by covalent modification of cysteine residues. In contrast to TRPA1 channels, modification of a single cysteine located in the N-terminal region of TRPV1 was necessary and sufficient for all the effects we observed. Our findings point to a conserved mechanism of activation in TRP channels, which provides new insights into the molecular basis of noxious stimuli detection.


Available from: Leon D Islas
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    • "Some compounds thought to be specific for the noxious cold receptor TRPA1 (see below) proved to activate TRPV1. This is the case of the pungent compound derived from onions, allicin (Macpherson et al., 2005; Salazar et al., 2008). The activation of TRPV1 is also produced by a fraction of the venom of the tarantula, Psalmopoeus cambridgei, that contains three cysteine knot (Kremeyer et al., 2010) peptides, dubbed vanillotoxins (Siemens et al., 2006). "
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    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.
    Thermal Sensors, First edited by León Islas, Feng Qin, 11/2014: chapter Gating of Thermally Activated Channels: pages 51-87; Elsevier., ISBN: 1063-5823
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    • "These channels play an important role in mediating neurogenic inflammation and pain induced by noxious chemicals or thermal stimuli. TRPA1 channels have ankyrin-like repeats in the N terminus that are rich in cysteine residues (Bandell et al., 2007; Macpherson et al., 2007) and TRPV1 channels have extracellular cysteines (Jin et al., 2004; Susankova et al., 2006) that react with electrophiles and other thiol modifying species via Michael addition to alter channel gating and excitability (Bandell et al., 2004; Macpherson et al., 2007; Salazar et al., 2008). It has been proposed that OA-NO 2 covalently modifies the negatively charged cysteine of TRP channels leading to changes in channel function (Rudolph and Freeman, 2009). "
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    ABSTRACT: Nitro-oleic acid (OA-NO2), an electrophilic fatty acid nitroalkene byproduct of redox reactions, activates transient receptor potential ion channels (TRPA1 and TRPV1) in primary sensory neurons. To test the possibility that signaling actions of OA-NO2 might modulate TRP channels, we examined: (1) interactions between OA-NO2 and other agonists for TRPA1 (allyl-isothiocyanate, AITC) and TRPV1 (capsaicin) in rat dissociated dorsal root ganglion cells using Ca(2+) imaging and patch clamp techniques and (2) interactions between these agents on sensory nerves in the rat hindpaw. Ca(2+) imaging revealed that brief application (15-30sec) of each of the three agonists induced homologous desensitization. Heterologous desensitization also occurred when one agonist was applied prior to another agonist. OA-NO2 was more effective in desensitizing the response to AITC than the response to capsaicin. Prolonged exposure to OA-NO2 (20min) had a similar desensitizing effect on AITC or capsaicin. Homologous and heterologous desensitization were also demonstrated with patch clamp recording. Deltamethrin, a phosphatase inhibitor, reduced the capsaicin or AITC induced desensitization of OA-NO2 but did not suppress the OA-NO2 induced desensitization of AITC or capsaicin, indicating that heterologous desensitization induced by either capsaicin or AITC occurs by a different mechanism than the desensitization produced by OA-NO2. Subcutaneous injection of OA-NO2 (2.5mM, 35μL) into a rat hindpaw induced delayed and prolonged nociceptive behavior. Homologous desensitization occurred with AITC and capsaicin when applied at 15minute intervals, but did not occur with OA-NO2 when applied at a 30min interval. Pretreatment with OA-NO2 reduced AITC-evoked nociceptive behaviors but did not alter capsaicin responses. These results raise the possibility that OA-NO2 might be useful clinically to reduce neurogenic inflammation and certain types of painful sensations by desensitizing TRPA1 expressing nociceptive afferents.
    Experimental Neurology 11/2013; 251. DOI:10.1016/j.expneurol.2013.10.020 · 4.70 Impact Factor
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    • "In addition, FRET is only sensitive to global conformational changes, but gives little information about localized structural changes. Certain structural and functional aspects of the TRPV1 and TRPV3 pore-domains have already been addressed by previous studies [16] [17] [18]. However, much less is known about how specifically temperature affects the pore structure. "
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    ABSTRACT: Thermosensation is mediated by ion channels that are highly temperature-sensitive. Several members of the family of transient receptor potential (TRP) ion channels are activated by cold or hot temperatures and have been shown to function as temperature sensors in vivo. The molecular mechanism of temperature-sensitivity of these ion channels is not understood. A number of domains or even single amino acids that regulate temperature-sensitivity have been identified in several TRP channels. However, it is unclear what precise conformational changes occur upon temperature activation. Here, we used the cysteine accessibility method to probe temperature-dependent conformations of single amino acids in TRP channels. We screened over 50 amino acids in the predicted outer pore domains of the heat-activated ion channels TRPV1 and TRPV3. In both ion channels we found residues that have temperature-dependent accessibilities to the extracellular solvent. The identified residues are located within the second predicted extracellular pore loop. These residues are identical or proximal to residues that were shown to be specifically required for temperature-activation, but not chemical activation. Our data precisely locate conformational changes upon temperature-activation within the outer pore domain. Collectively, this suggests that these specific residues and the second predicted pore loop in general are crucial for the temperature-activation mechanism of these heat-activated thermoTRPs.
    PLoS ONE 03/2013; 8(3):e59593. DOI:10.1371/journal.pone.0059593 · 3.23 Impact Factor
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