scholarly journals Drosophila menthol sensitivity and the Precambrian origins of transient receptor potential-dependent chemosensation

2019 ◽  
Vol 374 (1785) ◽  
pp. 20190369 ◽  
Author(s):  
Nathaniel J. Himmel ◽  
Jamin M. Letcher ◽  
Akira Sakurai ◽  
Thomas R. Gray ◽  
Maggie N. Benson ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Transient Receptor Potential ◽  
Trp Channels ◽  
Receptor Potential ◽  
Cation Channels ◽  
Transient Receptor Potential Melastatin ◽  
Growing Body ◽  
Sensitivity Studies ◽  
Transient Receptor ◽  
Class Iv

Transient receptor potential (TRP) cation channels are highly conserved, polymodal sensors which respond to a wide variety of stimuli. Perhaps most notably, TRP channels serve critical functions in nociception and pain. A growing body of evidence suggests that transient receptor potential melastatin (TRPM) and transient receptor potential ankyrin (TRPA) thermal and electrophile sensitivities predate the protostome–deuterostome split (greater than 550 Ma). However, TRPM and TRPA channels are also thought to detect modified terpenes (e.g. menthol). Although terpenoids like menthol are thought to be aversive and/or harmful to insects, mechanistic sensitivity studies have been largely restricted to chordates. Furthermore, it is unknown if TRP-menthol sensing is as ancient as thermal and/or electrophile sensitivity. Combining genetic, optical, electrophysiological, behavioural and phylogenetic approaches, we tested the hypothesis that insect TRP channels play a conserved role in menthol sensing. We found that topical application of menthol to Drosophila melanogaster larvae elicits a Trpm - and TrpA1 -dependent nocifensive rolling behaviour, which requires activation of Class IV nociceptor neurons. Further, in characterizing the evolution of TRP channels, we put forth the hypotheses that three previously undescribed TRPM channel clades (basal, αTRPM and βTRPM), as well as TRPs with residues critical for menthol sensing, were present in ancestral bilaterians. This article is part of the Theo Murphy meeting issue ‘Evolution of mechanisms and behaviour important for pain’.

scholarly journals Drosophila menthol sensitivity and the Precambrian origins of TRP-dependent chemosensation

2019 ◽  
Author(s):  
Nathaniel J. Himmel ◽  
Jamin M. Letcher ◽  
Akira Sakurai ◽  
Thomas R. Gray ◽  
Maggie N. Benson ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Topical Application ◽  
Transient Receptor Potential ◽  
Trp Channels ◽  
Receptor Potential ◽  
Cation Channels ◽  
Growing Body ◽  
Sensitivity Studies ◽  
Transient Receptor ◽  
Class Iv

AbstractTransient receptor potential (TRP) cation channels are highly conserved, polymodal sensors which respond to a wide variety of stimuli. Perhaps most notably, TRP channels serve critical functions in nociception and pain. A growing body of evidence suggests that TRPM (Melastatin) and TRPA (Ankyrin) thermal and electrophile sensitivities predate the protostome-deuterostome split (>550 million years ago). However, TRPM and TRPA channels are also thought to detect modified terpenes (e.g., menthol). Although terpenoids like menthol are thought to be aversive and/or harmful to insects, mechanistic sensitivity studies have been largely restricted to chordates. Furthermore, it is unknown if TRP-menthol sensing is as ancient as thermal and/or electrophile sensitivity. Combining genetic, optical, electrophysiological, behavioural, and phylogenetic approaches, we tested the hypothesis that insect TRP channels play a conserved role in menthol sensing. We found that topical application of menthol to Drosophila melanogaster larvae elicits a Trpm- and TrpA1-dependent nocifensive rolling behaviour, which requires activation of Class IV nociceptor neurons. Further, in characterizing the evolution of TRP channels, we put forth the hypotheses that 3 previously undescribed TRPM channel clades (basal, αTRPM, and βTRPM), as well as TRPs with residues critical for menthol sensing, were present in ancestral bilaterians.

scholarly journals Structure of full-length human TRPM4

2018 ◽  
Vol 115 (10) ◽  
pp. 2377-2382 ◽  
Author(s):  
Jingjing Duan ◽  
Zongli Li ◽  
Jian Li ◽  
Ana Santa-Cruz ◽  
Silvia Sanchez-Martinez ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Trp Channels ◽  
Coiled Coil ◽  
Receptor Potential ◽  
Lipid Binding ◽  
Full Length ◽  
Intramolecular Interactions ◽  
Coiled Coil Domain ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Transient receptor potential melastatin subfamily member 4 (TRPM4) is a widely distributed, calcium-activated, monovalent-selective cation channel. Mutations in human TRPM4 (hTRPM4) result in progressive familial heart block. Here, we report the electron cryomicroscopy structure of hTRPM4 in a closed, Na+-bound, apo state at pH 7.5 to an overall resolution of 3.7 Å. Five partially hydrated sodium ions are proposed to occupy the center of the conduction pore and the entrance to the coiled-coil domain. We identify an upper gate in the selectivity filter and a lower gate at the entrance to the cytoplasmic coiled-coil domain. Intramolecular interactions exist between the TRP domain and the S4–S5 linker, N-terminal domain, and N and C termini. Finally, we identify aromatic interactions via π–π bonds and cation–π bonds, glycosylation at an N-linked extracellular site, a pore-loop disulfide bond, and 24 lipid binding sites. We compare and contrast this structure with other TRP channels and discuss potential mechanisms of regulation and gating of human full-length TRPM4.

scholarly journals Structural insights into TRPM8 inhibition and desensitization

Science ◽  
2019 ◽  
Vol 365 (6460) ◽  
pp. 1434-1440 ◽  
Author(s):  
Melinda M. Diver ◽  
Yifan Cheng ◽  
David Julius
Keyword(s):  
Conformational Changes ◽  
Calcium Binding ◽  
Transient Receptor Potential ◽  
Trp Channels ◽  
Receptor Potential ◽  
Binding Pocket ◽  
Chemical Structures ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor ◽  
Large Rearrangements

The transient receptor potential melastatin 8 (TRPM8) ion channel is the primary detector of environmental cold and an important target for treating pathological cold hypersensitivity. Here, we present cryo–electron microscopy structures of TRPM8 in ligand-free, antagonist-bound, or calcium-bound forms, revealing how robust conformational changes give rise to two nonconducting states, closed and desensitized. We describe a malleable ligand-binding pocket that accommodates drugs of diverse chemical structures, and we delineate the ion permeation pathway, including the contribution of lipids to pore architecture. Furthermore, we show that direct calcium binding mediates stimulus-evoked desensitization, clarifying this important mechanism of sensory adaptation. We observe large rearrangements within the S4-S5 linker that reposition the S1-S4 and pore domains relative to the TRP helix, leading us to propose a distinct model for modulation of TRPM8 and possibly other TRP channels.

Differential regulation of transient receptor potential melastatin 6 and 7 cation channels by ANG II in vascular smooth muscle cells from spontaneously hypertensive rats

2006 ◽  
Vol 290 (1) ◽  
pp. R73-R78 ◽  
Author(s):  
Rhian M. Touyz ◽  
Ying He ◽  
Augusto C. I. Montezano ◽  
Guoying Yao ◽  
Vladimir Chubanov ◽  
...  
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Cation Channels ◽  
Ang Ii ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Annexin 1 ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Intracellular Mg2+ depletion has been implicated in vascular dysfunction in hypertension. We demonstrated that transient receptor potential melastatin 7 (TRPM7) cation channels mediate Mg2+ influx in VSMCs. Whether this plays a role in [Mg2+]i deficiency in hypertension is unclear. Here, we tested the hypothesis that downregulation of TRPM7 and its homologue TRPM6 is associated with reduced [Mg2+]i and that ANG II negatively regulates TRPM6/7 in vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR). Cultured VSMCs from Wistar Kyoto (WKY) and SHR were studied. mRNA and protein expression of TRPM6 and TRPM7 were assessed by RT-PCR and immunoblotting, respectively. Translocation of annexin-1, specific TRPM7 substrate, was measured as an index of TRPM7 activation. [Mg2+]i was determined using mag fura-2. VSMCs from WKY and SHR express TRPM6 and TRPM7. Basal TRPM6 expression was similar in WKY and SHR, but basal TRPM7 content was lower in VSMCs from SHR vs. WKY. This was associated with significantly reduced [Mg2+]i in SHR cells ( P < 0.01). ANG II time-dependently increased TRPM6 expression, with similar responses in WKY and SHR. ANG II significantly increased TRPM7 expression in WKY ( P < 0.05), but not in SHR. Annexin-1 translocation was reduced 1.5–2-fold in SHR vs. WKY. Our findings demonstrate that TRPM6 and TRPM7 are differentially regulated in VSMCs from SHR and WKY. Whereas TRPM6 is unaltered in SHR, expression of TRPM7 is blunted. This was associated with attenuated annexin-1 translocation and decreased VSMC [Mg2+]i in SHR. Downregulation of TRPM7, but not TRPM6, may play a role in altered Mg2+ homeostasis in VSMCs from SHR.

scholarly journals A TRiP Through the Roles of Transient Receptor Potential Cation Channels in Type 2 Upper Airway Inflammation

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Wout Backaert ◽  
Brecht Steelant ◽  
Peter W. Hellings ◽  
Karel Talavera ◽  
Laura Van Gerven
Keyword(s):  
Airway Inflammation ◽  
Transient Receptor Potential ◽  
Trp Channels ◽  
Upper Airway ◽  
Receptor Potential ◽  
Cation Channels ◽  
Cellular Functions ◽  
Upper Airways ◽  
Transient Receptor

Abstract Purpose of Review Despite their high prevalence, the pathophysiology of allergic rhinitis (AR) and chronic rhinosinusitis (CRS) remains unclear. Recently, transient receptor potential (TRP) cation channels emerged as important players in type 2 upper airway inflammatory disorders. In this review, we aim to discuss known and yet to be explored roles of TRP channels in the pathophysiology of AR and CRS with nasal polyps. Recent Findings TRP channels participate in a plethora of cellular functions and are expressed on T cells, mast cells, respiratory epithelial cells, and sensory neurons of the upper airways. In chronic upper airway inflammation, TRP vanilloid 1 is mostly studied in relation to nasal hyperreactivity. Several other TRP channels such as TRP vanilloid 4, TRP ankyrin 1, TRP melastatin channels, and TRP canonical channels also have important functions, rendering them potential targets for therapy. Summary The role of TRP channels in type 2 inflammatory upper airway diseases is steadily being uncovered and increasingly recognized. Modulation of TRP channels may offer therapeutic perspectives.

scholarly journals Transient Receptor Potential Cation Channels in Disease

2007 ◽  
Vol 87 (1) ◽  
pp. 165-217 ◽  
Author(s):  
Bernd Nilius ◽  
Grzegorz Owsianik ◽  
Thomas Voets ◽  
John A. Peters
Keyword(s):  
Transient Receptor Potential ◽  
Trp Channels ◽  
Divalent Cations ◽  
Receptor Potential ◽  
Hereditary Diseases ◽  
Cation Channels ◽  
Cell Functions ◽  
Transient Receptor ◽  
Trp Genes ◽  
The Impact

The transient receptor potential (TRP) superfamily consists of a large number of cation channels that are mostly permeable to both monovalent and divalent cations. The 28 mammalian TRP channels can be subdivided into six main subfamilies: the TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), and the TRPA (ankyrin) groups. TRP channels are expressed in almost every tissue and cell type and play an important role in the regulation of various cell functions. Currently, significant scientific effort is being devoted to understanding the physiology of TRP channels and their relationship to human diseases. At this point, only a few channelopathies in which defects in TRP genes are the direct cause of cellular dysfunction have been identified. In addition, mapping of TRP genes to susceptible chromosome regions (e.g., translocations, breakpoint intervals, increased frequency of polymorphisms) has been considered suggestive of the involvement of these channels in hereditary diseases. Moreover, strong indications of the involvement of TRP channels in several diseases come from correlations between levels of channel expression and disease symptoms. Finally, TRP channels are involved in some systemic diseases due to their role as targets for irritants, inflammation products, and xenobiotic toxins. The analysis of transgenic models allows further extrapolations of TRP channel deficiency to human physiology and disease. In this review, we provide an overview of the impact of TRP channels on the pathogenesis of several diseases and identify several TRPs for which a causal pathogenic role might be anticipated.

scholarly journals Transient receptor potential melastatin 3 is a phosphoinositide-dependent ion channel

2015 ◽  
Vol 146 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Doreen Badheka ◽  
Istvan Borbiro ◽  
Tibor Rohacs
Keyword(s):  
Ion Channel ◽  
Transient Receptor Potential ◽  
Kinase Inhibitors ◽  
Trp Channels ◽  
Receptor Potential ◽  
Channel Activity ◽  
Intact Cells ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor ◽  
Phosphatidylinositol 4

Phosphoinositides are emerging as general regulators of the functionally diverse transient receptor potential (TRP) ion channel family. Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) has been reported to positively regulate many TRP channels, but in several cases phosphoinositide regulation is controversial. TRP melastatin 3 (TRPM3) is a heat-activated ion channel that is also stimulated by chemical agonists, such as pregnenolone sulfate. Here, we used a wide array of approaches to determine the effects of phosphoinositides on TRPM3. We found that channel activity in excised inside-out patches decreased over time (rundown), an attribute of PI(4,5)P2-dependent ion channels. Channel activity could be restored by application of either synthetic dioctanoyl (diC8) or natural arachidonyl stearyl (AASt) PI(4,5)P2. The PI(4,5)P2 precursor phosphatidylinositol 4-phosphate (PI(4)P) was less effective at restoring channel activity. TRPM3 currents were also restored by MgATP, an effect which was inhibited by two different phosphatidylinositol 4-kinase inhibitors, or by pretreatment with a phosphatidylinositol-specific phospholipase C (PI-PLC) enzyme, indicating that MgATP acted by generating phosphoinositides. In intact cells, reduction of PI(4,5)P2 levels by chemically inducible phosphoinositide phosphatases or a voltage-sensitive 5′-phosphatase inhibited channel activity. Activation of PLC via muscarinic receptors also inhibited TRPM3 channel activity. Overall, our data indicate that TRPM3 is a phosphoinositide-dependent ion channel and that decreasing PI(4,5)P2 abundance limits its activity. As all other members of the TRPM family have also been shown to require PI(4,5)P2 for activity, our data establish PI(4,5)P2 as a general positive cofactor of this ion channel subfamily.

scholarly journals Nitric oxide signals through IRAG to inhibit TRPM4 channels and dilate cerebral arteries

Function ◽  
2021 ◽  
Author(s):  
Sher Ali ◽  
Alfredo Sanchez Solano ◽  
Albert L Gonzales ◽  
Pratish Thakore ◽  
Vivek Krishnan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Smooth Muscle Cells ◽  
Blood Vessels ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Cation Channels ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Abstract Nitric oxide (NO) relaxes vascular smooth muscle cells (SMCs) and dilates blood vessels by increasing intracellular levels of cyclic guanosine monophosphate (cGMP), which stimulates the activity of cGMP-dependent protein kinase (PKG). However, the vasodilator mechanisms downstream of PKG remain incompletely understood. Here, we found that transient receptor potential melastatin 4 (TRPM4) cation channels, which are activated by Ca2+ released from the sarcoplasmic reticulum (SR) through inositol triphosphate receptors (IP3Rs) under native conditions, are essential for SMC membrane depolarization and vasoconstriction. We hypothesized that signaling via the NO/cGMP/PKG pathway causes vasodilation by inhibiting TRPM4. We found that TRPM4 currents activated by stretching the plasma membrane or directly activating IP3Rs were suppressed by exogenous NO or a membrane-permeable cGMP analog, the latter of which also impaired IP3R-mediated release of Ca2+ from the SR. The effects of NO on TRPM4 activity were blocked by inhibition of soluble guanylyl cyclase or PKG. Notably, upon phosphorylation by PKG, IRAG (IP3R-associated PKG substrate) inhibited IP3R-mediated Ca2+ release, and knockdown of IRAG expression diminished NO-mediated inhibition of TRPM4 activity and vasodilation. Using superresolution microscopy, we found that IRAG, PKG, and IP3Rs form a nanoscale signaling complex on the SR of SMCs. We conclude that NO/cGMP/PKG signaling through IRAG inhibits IP3R-dependent activation of TRPM4 channels in SMCs to dilate arteries. Significance Statement: Nitric oxide (NO) is a gaseous vasodilator produced by endothelial cells that is essential for cardiovascular function. Although NO-mediated signaling pathways have been intensively studied, the mechanisms by which they relax smooth muscle cells (SMCs) to dilate blood vessels remain incompletely understood. In this study, we show that NO causes vasodilation by inhibiting the activity of Ca2+-dependent TRPM4 (transient receptor potential melastatin 4) cation channels. Probing further, we found that NO does not act directly on TRPM4 but instead initiates a signaling cascade that inhibits its activation by blocking the release of Ca2+ from the sarcoplasmic reticulum. Thus, our findings reveal the essential molecular pathways of NO-induced vasodilation—a fundamental unresolved concept in cardiovascular physiology.

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