Pore region of TRPV3 ion channel is specifically required for heat activation

Grandl, Jörg; Hu, Hongzhen; Bandell, Michael; Bursulaya, Badry; Schmidt, Manuela; Petrus, Matt; Patapoutian, Ardem

doi:10.1038/nn.2169

Cited by 165 publications

(196 citation statements)

References 38 publications

Supporting

Mentioning

189

Contrasting

Order By: Relevance

“…Regardless whether H426 constitutes a 2-APB binding site or not, these results show that 2-APB-activation of TRPV3 can be separated from all other agonists. Recently, we have identified a distinct segment close to the TRPV3 pore region that is specifically required for heat but not 2-APB-, camphor-, or voltage-modulation of the channel (20). Together, these findings support a hypothesis in which various modulators of TRPV3 have disparate activation pathways that allosterically couple to gate the channel (1).…”

Section: Discussionsupporting

confidence: 65%

“…As an initial approach to this question, we have focused on identifying structural elements that are specifically required for sensitivity of thermoTRPs to each individual stimulus (20,31). Our results show that 2 cytoplasmic residues are each required for activation of TRPV3 by 2-APB, but not by camphor.…”

Section: Discussionmentioning

confidence: 95%

“…In the absence of chemical stimulators (for example camphor or 2-APB), voltage steps from Ϫ120 to ϩ180 mV (20 mV step) did not activate currents in HEK293 cells transfected with wild-type TRPV3, indicating that TRPV3 (unlike TRPV1 and TRPM8) is not activated by voltage alone at the range tested here (20,22). However, in the presence of 30 M 2-APB, a voltage-dependent current was activated (Fig.…”

Section: Voltage-dependent Response Remained Intact In 2-apb Mutantsmentioning

confidence: 89%

“…Mutant constructs were transfected into human embryonic kidney (HEK293) cells, and calcium responses evoked by heat (42°C), 25 M 2-APB, and 1.75 mM camphor were monitored in a fluorescence imaging plate reader (FLIPR). We recently described the identification of residues specifically required for TRPV3 heat activation (20). Here, we focused on the 2-APB and camphor dataset to identify residues specifically required for chemical responses.…”

Section: Identification Of Mutations Specifically Affecting 2-apb Resmentioning

confidence: 99%

See 3 more Smart Citations

Two amino acid residues determine 2-APB sensitivity of the ion channels TRPV3 and TRPV4

Grandl

Bandell

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

105

View full text Add to dashboard Cite

Temperature-activated transient receptor potential ion channels (thermoTRPs) are polymodal detectors of various stimuli including temperature, voltage, and chemicals. To date, it is not known how TRP channels integrate the action of such disparate stimuli. Identifying specific residues required for channel-activation by distinct stimuli is necessary for understanding overall TRP channel function. TRPV3 is activated by warm temperatures and various chemicals, and is modulated by voltage. One potent activator of TRPV3 is 2-aminoethyl diphenylborinate (2-APB), a synthetic chemical that modulates many TRP channels. In a high-throughput mutagenesis screen of Ϸ14,000 mutated mouse TRPV3 clones, we found 2 residues (H426 and R696) specifically required for sensitivity of TRPV3 to 2-APB, but not to camphor or voltage. The cytoplasmic N-terminal mutation H426N in human, dog, and frog TRPV3 also effectively abolished 2-APB activation without affecting camphor responses. Interestingly, chicken TRPV3 is weakly sensitive to 2-APB, and the equivalent residue at 426 is an asparagine (N). Mutating this residue to histidine induced 2-APB sensitivity of chicken TRPV3 to levels comparable for other TRPV3 orthologs. The cytoplasmic C-terminal mutation R696K in the TRP box displayed 2-APB specific deficits only in the presence of extracellular calcium, suggesting involvement in gating. TRPV4, a related thermoTRP, is 2-APB insensitive and has variant sequences at both residues identified here. Remarkably, mutating these 2 residues in TRPV4 to TRPV3 sequences (N426H and W737R) was sufficient to induce TRPV3-like 2-APB sensitivity. Therefore, 2-APB activation of TRPV3 is separable from other activation mechanisms, and depends on 2 cytoplasmic residues.A subset of transient receptor potential (TRP) ion channels have important roles in sensory biology, including pain and thermosensation (1-4). The requirement of several so-called thermoTRPs in thermosensation in vivo has been demonstrated, suggesting that these ion channels have a physiological role as molecular thermometers (5-9). Thresholds of temperatureactivation of thermoTRPs are shifted in the presence of chemical agonists, effectively modulating thermosensation (1, 10-12). Several natural and synthetic compounds have been identified as agonists or antagonists for each of the thermoTRPs (13). However, little is known about how these chemicals modulate TRP channel activity.TRPV3, one of these thermoTRPs, is a nonselective cation channel expressed primarily in mammalian keratinocytes, and is involved in thermosensation (4,7,14). Like other thermoTRP channels, TRPV3 is a polymodal detector of temperature (heat) and chemicals. TRPV3 agonists include structurally-related natural compounds such as camphor, thymol, and carvacrol (15, 16). One of the most potent TRPV3 agonists is 2-aminoethyl diphenylborinate (2-APB), a synthetic compound that modulates the activity of many ion channels. It is a common activator of the heat-gated TRPV ion-channels TRPV1, TRPV2, and TRPV3 (17,18). Besides i...

show abstract

Section: Discussionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 95%

Section: Voltage-dependent Response Remained Intact In 2-apb Mutantsmentioning

confidence: 89%

Section: Identification Of Mutations Specifically Affecting 2-apb Resmentioning

confidence: 99%

See 2 more Smart Citations

Two amino acid residues determine 2-APB sensitivity of the ion channels TRPV3 and TRPV4

Grandl

Bandell

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

105

View full text Add to dashboard Cite

show abstract

“…Indeed, the sites affecting gating spread across the outer pore landscape. Of particular interests are a number of sites that when mutated, lead to permanent opening or closing of the temperature-activation gate (1)(2)(3).…”

mentioning

confidence: 99%

Reply to Yao et al.: Is the pore turret just thermoTRP channels’ appendix?

Yang

Cui

Wang

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Numerous studies of thermosensitive transient receptor potential (thermoTRP) channels have focused on the outer pore that contains sites critical for the channel's sensitivity to temperature, acidification, spider toxin, and other gating modulators (Fig. 1). Two segments of each subunit contribute to the outer pore structure: one is between S5 and the pore helix, the other is between the selectivity filter and S6. For the convenience of discussion, we call them the large turret and the small turret, respectively. From the available structural information of tetrameric channels, it is expected that the two turrets interact extensively. Indeed, the sites affecting gating spread across the outer pore landscape. Of particular interests are a number of sites that when mutated, lead to permanent opening or closing of the temperature-activation gate (1-3).In agreement with these findings, our study demonstrated that the large turret is part of the temperature-activation pathway (4). This conclusion is based on experimental results that provided thermodynamic, functional, and structural information. Yao and colleagues (5) question our interpretation of one of these experiments, in which changing the large turret structure by sequence replacement yielded functional channels with no apparent temperature gating. Because the mutant channels exhibited near-normal permeation properties and capsaicin activation, structural perturbation is not nonspecific but limited to the temperature gating process-that is to say, the large turret is important for temperature gating. This interpretation is consistent with the observation that site-directed fluorescence recordings revealed large turret movement during heat activation but not capsaicin activation (4).Yao and colleagues object to this interpretation because they recorded temperature-induced whole-cell currents from a rat TRPV1 deletion mutant of a very similar region of the large turret (5). What remains unknown is the relative amplitude of these currents to the capsaicin-induced current from the same cell. In our mouse TRPV1 replacement mutant, there was a tiny heat response [figure 3b of our original report (4)] that, compared to the capsaicin-induced current, represents a very low open probability. The most straightforward interpretation of this phenomenon is that temperature activation is impaired. Interestingly, reduction in heat response was previously reported by the same group in mutant channels generated from the deletion background (6). They noticed "a large irreversible reduction of the capsaicin current after heating." The selective impairment of temperature sensitivity observed in both our study and that of Yao et al. (6) may be mechanistically related.One important but often overlooked issue is that the activity of all ion channels (as well as nonchannel proteins) exhibit temperature sensitivity. The universal temperature-dependence of channel gating, having a Q 10 value ranging from 3 to 7 in most cases, reflects a gain in kinetic energy upon heating that favors p...

show abstract

Ion‐Channel Modulators: More Diversity Than Previously Thought

et al. 2011

View full text Add to dashboard Cite

Ion-channel function can be modified in various ways. For example, numerous studies have shown that currents through voltage-gated ion channels are affected by pore block or modification of voltage dependence of activation/inactivation. Recent experiments performed on various ion channels show that allosteric modulation is an important mechanism for affecting channel function. For instance, in K(Ca)2 (formerly SK) channels, the prototypic "blocker" apamin prevents conduction by an allosteric mechanism, while TRPV1 channels are prevented from closing by a tarantula toxin, DkTx, through an interaction with residues located away from the selectivity filter. The recent evidence, therefore, suggests that in several ion channels, the region around the outer mouth of the pore is rich in binding sites and could be exploited therapeutically. These discoveries also suggest that the pharmacological vocabulary should be adapted to define these various actions.

show abstract

Pore region of TRPV3 ion channel is specifically required for heat activation

Cited by 165 publications

References 38 publications

Two amino acid residues determine 2-APB sensitivity of the ion channels TRPV3 and TRPV4

Two amino acid residues determine 2-APB sensitivity of the ion channels TRPV3 and TRPV4

Reply to Yao et al.: Is the pore turret just thermoTRP channels’ appendix?

Ion‐Channel Modulators: More Diversity Than Previously Thought

Contact Info

Product

Resources

About