Coordinating activation of endo-lysosomal two-pore channels and TRP mucolipins.

Two-pore channels and TRP mucolipins are ubiquitous endo-lysosomal cation channels of pathophysiological relevance. Both are Ca2+-permeable and regulated by phosphoinositides, principally PI(3,5)P2. Accumulating evidence has uncovered synergistic channel activation by PI(3,5)P2 and endogenous metabolites such as the Ca2+ mobilizing messenger NAADP, synthetic agonists including approved drugs and physical cues such as voltage and osmotic pressure. Here, we provide an overview of this coordination.

Transient Receptor Potential Channels in the Healthy and Diseased Blood-Brain Barrier.

The large family of transient receptor potential (TRP) channels are integral membrane proteins that function as environmental sensors and act as ion channels after activation by mechanical (touch), physical (heat, pain), and chemical stimuli (pungent compounds such as capsaicin). Most TRP channels are localized in the plasma membrane of cells but some of them are localized in membranes of organelles and function as intracellular Ca2+-ion channels. TRP channels are involved in neurological disorders but their precise role(s) and relevance in these disorders are not clear. Endothelial cells of the blood-brain barrier (BBB) express TRP channels such as TRP vanilloid 1-4 and are involved in thermal detection by regulating BBB permeability. In neurological disorders, TRP channels in the BBB are responsible for edema formation in the brain. Therefore, drug design to modulate locally activity of TRP channels in the BBB is a hot topic. Today, the application of TRP channel antagonists against neurological disorders is still limited.

Hypothalamic TRPM8 and TRPA1 ion channel genes in the regulation of temperature homeostasis at water balance changes.

The role of the hypothalamic cold-sensitive ion channels - transient receptor potential melastatin 8 (TRPM8) and transient receptor potential ankyrin 1 (TRPA1) in homeostatic systems of thermoregulation and water-salt balance - is not clear. The interaction of homeostatic systems of thermoregulation and water-salt balance without additional temperature load did not receive due attention, too. On the models of water-balance disturbance, we tried to elucidate some aspect of these problems. Body temperature (Tbody), O2 consumption, CO2 excretion, electrical muscle activity (EMA), temperature of tail skin (Ttail), plasma osmolality, as well as gene expression of hypothalamic TRPM8 and TRPA1 have been registered in rats of 3 groups: control; water-deprived (3 days under dry-eating); and hyperhydrated (6 days without dry food, drinking liquid 4 % sucrose). No relationship was observed between plasma osmolality and gene expression of Trpm8 and Trpa1. In water-deprived rats, the constriction of skin vessels, increased fat metabolism by 10 % and increased EMA by 48 % allowed the animals to maintain Tbody unchanged. The hyperhydrated rats did not develop sufficient mechanisms, and their Tbody decreased by 0.8 °C. The development of reactions was correlated with the expression of genes of thermosensitive ion channels in the anterior hypothalamus. Ttail had a direct correlation with the expression of the Trpm8 gene, whereas EMA directly correlated with the expression of the Trpa1 gene in water-deprived group. The obtained data attract attention from the point of view of management and correction of physiological functions by modulating the ion channel gene expression.

Roles of TRP and PIEZO receptors in autoimmune diseases.

Autoimmune diseases are pathological autoimmune reactions in the body caused by various factors, which can lead to tissue damage and organ dysfunction. They can be divided into organ-specific and systemic autoimmune diseases. These diseases usually involve various body systems, including the blood, muscles, bones, joints and soft tissues. The transient receptor potential (TRP) and PIEZO receptors, which resulted in David Julius and Ardem Patapoutian winning the Nobel Prize in Physiology or Medicine in 2021, attracted people's attention. Most current studies on TRP and PIEZO receptors in autoimmune diseases have been carried out on animal model, only few clinical studies have been conducted. Therefore, this study aimed to review existing studies on TRP and PIEZO to understand the roles of these receptors in autoimmune diseases, which may help elucidate novel treatment strategies.

TRPV Channels in Osteoarthritis: A Comprehensive Review.

Osteoarthritis (OA) is a debilitating joint disorder that affects millions of people worldwide. Despite its prevalence, our understanding of the underlying mechanisms remains incomplete. In recent years, transient receptor potential vanilloid (TRPV) channels have emerged as key players in OA pathogenesis. This review provides an in-depth exploration of the role of the TRPV pathway in OA, encompassing its involvement in pain perception, inflammation, and mechanotransduction. Furthermore, we discuss the latest research findings, potential therapeutic strategies, and future directions in the field, shedding light on the multifaceted nature of TRPV channels in OA.

Ca2+ Depletion in the ER Causes Store-Operated Ca2+ Entry via the TRPC6 Channel in Mouse Brown Adipocytes.

beta3-adrenergic activation causes Ca2+ release from the mitochondria and subsequent Ca2+ release from the endoplasmic reticulum (ER), evoking store-operated Ca2+ entry (SOCE) due to Ca2+ depletion from the ER in mouse brown adipocytes. In this study, we investigated how Ca2+ depletion from the ER elicits SOCE in mouse brown adipocytes using fluorometry of intracellular Ca2+ concentration ([Ca2+]i). The administration of cyclopiazonic acid (CPA), a reversible sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) pump blocker in the ER, caused an increase in [Ca2+]i. Moreover, CPA induced SOCE was suppressed by the administration of a Ca2+ free Krebs solution and the transient receptor potential canonical 6 (TRPC6) selective blockers 2-APB, ML-9 and GsMTx-4 but not Pico145, which blocks TRPC1/4/5. Administration of TRPC6 channel agonist 1-oleoyl-2-acetyl-sn-glycerol (OAG) and flufenamic acid elicited Ca2+ entry. Moreover, our RT-PCR analyses detected mRNAs for TRPC6 in brown adipose tissues. In addition, western blot analyses showed the expression of the TRPC6 protein. Thus, TRPC6 is one of the Ca2+ pathways involved in SOCE. These modes of Ca2+ entry provide the basis for heat production via activation of Ca2+-dependent dehydrogenase and the expression of uncoupling protein 1 (UCP1). Enhancing thermogenic metabolism in brown adipocytes may serve as broad therapeutic utility to reduce obesity and metabolic syndrome.

Discovery of TRPA1 Antagonist GDC-6599: Derisking Preclinical Toxicity and Aldehyde Oxidase Metabolism with a Potential First-in-Class Therapy for Respiratory Disease.

Transient receptor potential ankyrin 1 (TRPA1) is a nonselective calcium ion channel highly expressed in the primary sensory neurons, functioning as a polymodal sensor for exogenous and endogenous stimuli, and has been implicated in neuropathic pain and respiratory disease. Herein, we describe the optimization of potent, selective, and orally bioavailable TRPA1 small molecule antagonists with strong in vivo target engagement in rodent models. Several lead molecules in preclinical single- and short-term repeat-dose toxicity studies exhibited profound prolongation of coagulation parameters. Based on a thorough investigative toxicology and clinical pathology analysis, anticoagulation effects in vivo are hypothesized to be manifested by a metabolite─generated by aldehyde oxidase (AO)─possessing a similar pharmacophore to known anticoagulants (i.e., coumarins, indandiones). Further optimization to block AO-mediated metabolism yielded compounds that ameliorated coagulation effects in vivo, resulting in the discovery and advancement of clinical candidate GDC-6599, currently in Phase II clinical trials for respiratory indications.

Porcine transient receptor potential channel 1 (TRPC1) regulates muscle growth via the Wnt/ß-catenin and Wnt/Ca2+ pathways.

Transient receptor potential canonical (TRPC) channels allow the intracellular entry of Ca2+ and play important roles in several physio-pathological processes. In this study, we constructed transgenic mice expressing porcine TRPC1 (Tg-pTRPC1) to verify the effects of TRPC1 on skeletal muscle growth and elucidate the underlying mechanism. Porcine TRPC1 increased the muscle mass, fiber cross-sectional area, and exercise endurance of mice and accelerated muscle repair and regeneration. TRPC1 overexpression enhanced ß-catenin expression and promoted myogenesis, which was partly reversed by inhibitors of ß-catenin. TRPC1 facilitated the accumulation of intracellular Ca2+ and nuclear translocation of the NFATC2/NFATC2IP complex involved in the Wnt/Ca2+ pathway, promoting muscle growth. Paired related homeobox 1 (Prrx1) promoted the expression of TRPC1, NFATC2, and NFATC2IP that participate in the regulation of muscle growth. Taken together, our findings indicate that porcine TRPC1 promoted by Prrx1 could regulate muscle development through activating the canonical Wnt/ß-catenin and non-canonical Wnt/Ca2+ pathways.

TRP Ion Channels in Immune Cells and Their Implications for Inflammation.

The transient receptor potential (TRP) ion channels act as cellular sensors and mediate a plethora of physiological processes, including somatosensation, proliferation, apoptosis, and metabolism. Under specific conditions, certain TRP channels are involved in inflammation and immune responses. Thus, focusing on the role of TRPs in immune system cells may contribute to resolving inflammation. In this review, we discuss the distribution of five subfamilies of mammalian TRP ion channels in immune system cells and how these ion channels function in inflammatory mechanisms. This review provides an overview of the current understanding of TRP ion channels in mediating inflammation and may offer potential avenues for therapeutic intervention.

TRPV1 Channel in Human Eosinophils: Functional Expression and Inflammatory Modulation.

The transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel expressed on sensory neurons and immune cells. We hypothesize that TRPV1 plays a role in human eosinophil function and is modulated by inflammatory conditions. TRPV1 expression on human eosinophils was examined by qPCR, flow cytometry, and immunohistochemistry, respectively. TRPV1 functionality was analyzed by investigating calcium flux, apoptosis, modulation by cytokines and acidic pH, and CD69 externalization using flow cytometry. Activation of TRPV1 induced calcium influx and prolonged survival. Although eosinophils were not directly activated by TRPV1 agonists, activation by IL-3 or GM-CSF was mainly restricted to TRPV1-positive eosinophils. TRPV1 surface content was increased by acidic pH, IL-3, IL-31, IL-33, TSLP, TNF-α, BDNF, and NGF-ß. Interestingly, TRPV1 was also expressed by eosinophils located in proximity to peripheral nerves in atopic dermatitis (AD) skin. In conclusion, eosinophils express functional TRPV1 channels which are increased by extracellular acidification and AD-related cytokines. Since eosinophils also express TRPV1 in AD skin, our results indicate an important role of TRPV1 for neuroimmune interaction mechanisms in itchy, inflammatory skin diseases, like AD.

Transient receptor potential (TRP) channels in Sebastes schlegelii: Genome-wide identification and ThermoTRP expression analysis under high-temperature.

Transient Receptor Potential (TRP) channels, essential for sensing environmental stimuli, are widely distributed. Among them, thermosensory TRP channels play a crucial role in temperature sensing and regulation. Sebastes schlegelii, a significant aquatic economic species, exhibits sensitivity to temperature across multiple aspects. In this study, we identified 18 SsTRP proteins using whole-genome scanning. Motif analysis revealed motif 2 in all TRP proteins, with conserved motifs in subfamilies. TRP-related domains, anchored repeats, and ion-transmembrane domains were found. Chromosome analysis showed 18 TRP genes on 11 chromosomes and a scaffold. Phylogenetics classified SsTRPs into four subfamilies: TRPM, TRPA, TRPV, and TRPC. In diverse organisms, four monophyletic subfamilies were identified. Additionally, we identified key TRP genes with significantly upregulated transcription levels under short-term (30 min) and long-term (3 days) exposure at 24 °C (optimal elevated temperature) and 27 °C (critical high temperature). We propose that genes upregulated at 30 min may be involved in the primary response process of temperature sensing, while genes upregulated at 3 days may participate in the secondary response process of temperature perception. This study lays the foundation for understanding the regulatory mechanisms of TRPs responses to environmental stimuli in S. schlegelii and other fishes.

Recent advances on the structure and the function relationships of the TRPV4 ion channel.

The members of the superfamily of Transient Receptor Potential (TRP) ion channels are physiologically important molecules that have been studied for many years and are still being intensively researched. Among the vanilloid TRP subfamily, the TRPV4 ion channel is an interesting protein due to its involvement in several essential physiological processes and in the development of various diseases. As in other proteins, changes in its function that lead to the development of pathological states, have been closely associated with modification of its regulation by different molecules, but also by the appearance of mutations which affect the structure and gating of the channel. In the last few years, some structures for the TRPV4 channel have been solved. Due to the importance of this protein in physiology, here we discuss the recent progress in determining the structure of the TRPV4 channel, which has been achieved in three species of animals (Xenopus tropicalis, Mus musculus, and Homo sapiens), highlighting conserved features as well as key differences among them and emphasizing the binding sites for some ligands that play crucial roles in its regulation.

High-throughput screening of transient receptor potential (TRP) channels in pterygium.

PURPOSE: Pterygium is a hyaline degenerative disease of the conjunctiva characterized by the progression of fibrovascular connective tissue from the bulbar conjunctiva to the cornea. The mechanism of pterygium formation is still not fully understood. Transient receptor potential (TRP) channels are a group of ion channels with distinct characteristics. Recent indications suggest TRP channels may play a significant regulatory role in pterygium development, but previous studies have mainly focused on in silico analysis. Accordingly, in the present study, we aimed to decipher the expression signatures and role of TRP channels in pterygium development. METHODS: The study encompassed a cohort of 45 patients matched for age and gender distribution, comprising 30 individuals with primary pterygium (PP) and 15 individuals with recurrent pterygium (RP). The control group consisted of unaffected conjunctival tissue obtained from the same set of patients. High-throughput screening of differentially expressed TRP channels in pterygium tissues was achieved with the help of Fluidigm 96.96 Dynamic Array Expression Chip and reactions were held in BioMark™ HD System Real-Time PCR platform. RESULTS: Statistically significant increases were found in the expression of 21 genes, mainly TRPA1 (p = 0.021), TRPC2 (p = 0.001), and TRPM8 (p = 0.003), in patients with PP, and in TRPC5 (p = 0.05), TRPM2 (p = 0.029), TRPM4 (p = 0.03), TRPM6 (p = 0.045), TRPM8 (p = 0.038), TRPV1 (p = 0.01) and TRPV4 (p = 0.025) genes in RP tissues. CONCLUSION: Collectively, TRP channel proteins appear to play pivotal roles in both the development and progression of pterygium, making them promising candidates for future therapeutic interventions in patients afflicted by this condition.

Non-electrophysiological techniques targeting transient receptor potential (TRP) gene of gastrointestinal tract.

Transient receptor potential (TRP) channels are cation channels related to a wide range of physical and chemical stimuli, they are expressed all along the gastrointestinal system, and a myriad of diseases are often associated with aberrant expression or mutation of the TRP gene, suggesting that TRPs are promising targets for drug therapy. Therefore, a better understanding of the information of TRPs in health and disease could facilitate the development of effective drugs for the treatment of gastrointestinal diseases like IBD. But there are very few generalizations about the experimental techniques studied in this field. In view of the promise of TRP as a therapeutic target, we discuss experimental methods that can be used for TRPs including their distribution, function and interaction with other proteins, as well as some promising emerging technologies to provide experimental methods for future studies.

Transient Receptor Potential Channels: Multiple Modulators of Peripheral Neuropathic Pain in Several Rodent Models.

Neuropathic pain, a prevalent chronic condition in clinical settings, has attracted widespread societal attention. This condition is characterized by a persistent pain state accompanied by affective and cognitive disruptions, significantly impacting patients' quality of life. However, current clinical therapies fall short of addressing its complexity. Thus, exploring the underlying molecular mechanism of neuropathic pain and identifying potential targets for intervention is highly warranted. The transient receptor potential (TRP) receptors, a class of widely distributed channel proteins, in the nervous system, play a crucial role in sensory signaling, cellular calcium regulation, and developmental influences. TRP ion channels are also responsible for various sensory responses including heat, cold, pain, and stress. This review highlights recent advances in understanding TRPs in various rodent models of neuropathic pain, aiming to uncover potential therapeutic targets for clinical management.

Propolis alleviates ulcerative colitis injury by inhibiting the protein kinase C - transient receptor potential cation channel subfamily V member 1 - calcitonin gene-related peptide/substance P (PKC-TRPV1-CGRP/SP) signaling axis.

This study investigated the protective effect of water-soluble propolis (WSP) on colonic tissues in ulcerative colitis (UC) and the role of the protein kinase C - transient receptor potential cation channel subfamily V member 1 - calcitonin gene-related peptide/substance P (PKC-TRPV1-CGRP/SP) signaling pathway. Male SD rats were divided into a control group, a UC model group, various WSP groups (Low-WSP, Medium-WSP, and High-WSP) with UC, and a salazosulfapyridine (SASP) positive control group with UC. After UC was established, the WSP and SASP groups were treated with WSP or SASP, respectively, for 7 d. Each day, body weight measurements were obtained, and the disease activity index (DAI) was recorded by observing fecal characteristics and blood in the stool. After the experiment, hematoxylin and eosin (HE) colonic tissue staining was performed to observe pathological changes, western blotting and immunohistochemistry were performed to detect PKC, TRPV1, CGRP, and SP expression in colonic tissues, and laser confocal microscopy was performed to observe the fluorescence colocalization of PKC/TRPV1, TRPV1/CGRP, and TRPV1/SP. HE staining showed significant colonic tissue structure disruption and inflammatory infiltration in the UC group. Western blotting and immunohistochemistry showed that the expression of PKC, TRPV1, CGRP, and SP in the colonic tissues of the UC group increased significantly compared with that of the control group. Compared with the UC group, the expression of PKC, TRPV1, CGRP, and SP in colonic tissues was significantly reduced in the High-WSP, Medium-WSP, and SASP groups. Immunofluorescence showed the colocalized expression of PKC/TRPV1, TRPV1/CGRP, and TRPV1/SP proteins in the colon tissue of the UC group was significantly reduced after WSP and SASP interventions compared with that of the control group. The results suggest that the mechanism of UC alleviation by propolis may inhibit the PKC-TRPV1-CGRP/SP signaling pathway and the release of inflammatory mediators, thus alleviating inflammation.

Modulation of Cisplatin Sensitivity through TRPML1-Mediated Lysosomal Exocytosis in Ovarian Cancer Cells: A Comprehensive Metabolomic Approach.

BACKGROUND: The lysosome has emerged as a promising target for overcoming chemoresistance, owing to its role in facilitating the lysosomal sequestration of drugs. The lysosomal calcium channel TRPML1 not only influences lysosomal biogenesis but also coordinates both endocytosis and exocytosis. This study explored the modulation of cisplatin sensitivity by regulating TRPML1-mediated lysosomal exocytosis and identified the metabolomic profile altered by TRPML1 inhibition. METHODS: We used four types of ovarian cancer cells: two cancer cell lines (OVCAR8 and TOV21G) and two patient-derived ovarian cancer cells. Metabolomic analyses were conducted to identify altered metabolites by TRPML1 inhibition. RESULTS: Lysosomal exocytosis in response to cisplatin was observed in resistant cancer cells, whereas the phenomenon was absent in sensitive cancer cells. Through the pharmacological intervention of TRPML1, lysosomal exocytosis was interrupted, leading to the sensitization of resistant cancer cells to cisplatin treatment. To assess the impact of lysosomal exocytosis on chemoresistance, we conducted an untargeted metabolomic analysis on cisplatin-resistant ovarian cancer cells with TRPML1 inhibition. Among the 1446 differentially identified metabolites, we focused on 84 significant metabolites. Metabolite set analysis revealed their involvement in diverse pathways. CONCLUSIONS: These findings collectively have the potential to enhance our understanding of the interplay between lysosomal exocytosis and chemoresistance, providing valuable insights for the development of innovative therapeutic strategies.

Flow-dependent regulation of rat mesenteric lymphatic vessel contractile response requires activation of endothelial TRPV4 channels.

OBJECTIVES: The objective of our study is to evaluate the involvement of the transient receptor potential vanilloid 4 (TRPV4) in the alteration of lymphatic pumping in response to flow and determine the signaling pathways involved. METHODS: We used immunofluorescence imaging and western blotting to assess TRPV4 expression in rat mesenteric lymphatic vessels. We examined inhibition of TRPV4 with HC067047, nitric oxide synthase (NOS) with L-NNA and cyclooxygenases (COXs) with indomethacin on the contractile response of pressurized lymphatic vessels to flow changes induced by a stepwise increase in pressure gradients, and the functionality of endothelial TRPV4 channels by measuring the intracellular Ca2+ response of primary lymphatic endothelial cell cultures to the selective agonist GSK1016790A. RESULTS: TRPV4 protein was expressed in both the endothelial and the smooth muscle layer of rat mesenteric lymphatics with high endothelial expression around the valve sites. When maintained under constant transmural pressure, most lymphatic vessels displayed a decrease in contraction frequency under conditions of flow and this effect was ablated through inhibition of NOS, COX or TRPV4. CONCLUSIONS: Our findings demonstrate a critical role for TRPV4 in the decrease in contraction frequency induced in lymphatic vessels by increases in flow rate via the production and action of nitric oxide and dilatory prostanoids.

ZBTB20 mediates stress-induced visceral hypersensitivity via activating the NF-κB/transient receptor potential channel pathway.

BACKGROUND: Psychological stress is a major trigger for visceral hypersensitivity (VH) in irritable bowel syndrome. The zinc finger protein ZBTB20 (ZBTB20) is implicated in somatic nociception via modulating transient receptor potential (TRP) channels, but its role in the development of VH is unclear. This study aimed to investigate the role of ZBTB20/TRP channel axis in stress-induced VH. METHODS: Rats were subjected to water avoidance stress (WAS) for 10 consecutive days. Small interfering RNA (siRNA) targeting ZBTB20 was intrathecally administered. Inhibitors of TRP channels, stress hormone receptors, and nuclear factor kappa-B (NF-κB) were administered. Visceromotor response to colorectal distension was recorded. Dorsal root ganglia (DRGs) were dissected for Western blot, coimmunoprecipitation, and chromatin immunoprecipitation. The DRG-derived neuron cell line was applied for specific research. KEY RESULTS: WAS-induced VH was suppressed by the inhibitor of TRPV1, TRPA1, or TRPM8, with enhanced expression of these channels in L6-S2 DRGs. The inhibitor of glucocorticoid receptor or ß2-adrenergic receptor counteracted WAS-induced VH and TRP channel expression. Concurrently, WAS-induced stress hormone-dependent ZBTB20 expression and NF-κB activation in DRGs. Intrathecally injected ZBTB20 siRNA or an NF-κB inhibitor repressed WAS-caused effect. In cultured DRG-derived neurons, stress hormones promoted nuclear translocation of ZBTB20, which preceded p65 nuclear translocation. And, ZBTB20 siRNA suppressed stress hormone-caused NF-κB activation. Finally, WAS enhanced p65 binding to the promoter of TRPV1, TRPA1, or TRPM8 in rat DRGs. CONCLUSIONS AND INFERENCES: ZBTB20 mediates stress-induced VH via activating NF-κB/TRP channel pathway in nociceptive sensory neurons.

Membrane lipid modulations by methyl-ß-cyclodextrin uncouple the Drosophila light-activated phospholipase C from TRP and TRPL channel gating.

Sterols are hydrophobic molecules, known to cluster signaling membrane-proteins in lipid rafts, while methyl-ß-cyclodextrin (MßCD) has been a major tool for modulating membrane-sterol content for studying its effect on membrane proteins, including the transient receptor potential (TRP) channels. The Drosophila light-sensitive TRP channels are activated downstream of a G-protein-coupled phospholipase Cß (PLC) cascade. In phototransduction, PLC is an enzyme that hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) generating diacylglycerol, inositol-tris-phosphate, and protons, leading to TRP and TRP-like (TRPL) channel openings. Here, we studied the effects of MßCD on Drosophila phototransduction using electrophysiology while fluorescently monitoring PIP2 hydrolysis, aiming to examine the effects of sterol modulation on PIP2 hydrolysis and the ensuing light-response in the native system. Incubation of photoreceptor cells with MßCD dramatically reduced the amplitude and kinetics of the TRP/TRPL-mediated light response. MßCD also suppressed PLC-dependent TRP/TRPL constitutive channel activity in the dark induced by mitochondrial uncouplers, but PLC-independent activation of the channels by linoleic acid was not affected. Furthermore, MßCD suppressed a constitutively active TRP mutant-channel, trpP365, suggesting that TRP channel activity is a target of MßCD action. Importantly, whole-cell voltage-clamp measurements from photoreceptors and simultaneously monitored PIP2-hydrolysis by translocation of fluorescently tagged Tubby protein domain, from the plasma membrane to the cytosol, revealed that MßCD virtually abolished the light response when having little effect on the light-activated PLC. Together, MßCD uncoupled TRP/TRPL channel gating from light-activated PLC and PIP2-hydrolysis suggesting the involvement of distinct nanoscopic lipid domains such as lipid rafts and PIP2 clusters in TRP/TRPL channel gating.