Our understanding of the general principles of the polymodal regulation of transient receptor potential (TRP) ion channels has grown impressively in recent years as a result of intense efforts in protein structure determination by cryo-electron microscopy. In particular, the high-resolution structures of various TRP channels captured in different conformations, a number of them determined in a membrane mimetic environment, have yielded valuable insights into their architecture, gating properties and the sites of their interactions with annular and regulatory lipids. The correct repertoire of these channels is, however, organized by supramolecular complexes that involve the localization of signaling proteins to sites of action, ensuring the specificity and speed of signal transduction events. As such, TRP ankyrin 1 (TRPA1), a major player involved in various pain conditions, localizes into cholesterol-rich sensory membrane microdomains, physically interacts with calmodulin, associates with the scaffolding A-kinase anchoring protein (AKAP) and forms functional complexes with the related TRPV1 channel. This perspective will contextualize the recent biochemical and functional studies with emerging structural data with the aim of enabling a more thorough interpretation of the results, which may ultimately help to understand the roles of TRPA1 under various physiological and pathophysiological pain conditions. We demonstrate that an alteration to the putative lipid-binding site containing a residue polymorphism associated with human asthma affects the cold sensitivity of TRPA1. Moreover, we present evidence that TRPA1 can interact with AKAP to prime the channel for opening. The structural bases underlying these interactions remain unclear and are definitely worth the attention of future studies.

• Publikační typ
• časopisecké články MeSH

The vanilloid transient receptor potential channel TRPV3 is a putative molecular thermosensor widely considered to be involved in cutaneous sensation, skin homeostasis, nociception, and pruritus. Repeated stimulation of TRPV3 by high temperatures above 50 °C progressively increases its responses and shifts the activation threshold to physiological temperatures. This use-dependence does not occur in the related heat-sensitive TRPV1 channel in which responses decrease, and the activation threshold is retained above 40 °C during activations. By combining structure-based mutagenesis, electrophysiology, and molecular modeling, we showed that chimeric replacement of the residues from the TRPV3 cytoplasmic inter-subunit interface (N251-E257) with the homologous residues of TRPV1 resulted in channels that, similarly to TRPV1, exhibited a lowered thermal threshold, were sensitized, and failed to close completely after intense stimulation. Crosslinking of this interface by the engineered disulfide bridge between substituted cysteines F259C and V385C (or, to a lesser extent, Y382C) locked the channel in an open state. On the other hand, mutation of a single residue within this region (E736) resulted in heat resistant channels. We propose that alterations in the cytoplasmic inter-subunit interface produce shifts in the channel gating equilibrium and that this domain is critical for the use-dependence of the heat sensitivity of TRPV3.

• MeSH
• cytoplazma metabolismus   MeSH
• HEK293 buňky MeSH
• kationtové kanály TRPV chemie   genetika   metabolismus   MeSH
• lidé MeSH
• mutace MeSH
• podjednotky proteinů chemie   genetika   metabolismus   MeSH
• proteinové domény MeSH
• simulace molekulární dynamiky MeSH
• vysoká teplota MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Transient receptor potential ankyrin 1 (TRPA1) is a temperature-sensitive ion channel activated by various pungent and irritant compounds that can produce pain in humans. Its activation involves an allosteric mechanism whereby electrophilic agonists evoke interactions within cytosolic domains and open the channel pore through an integrated nexus formed by intracellular membrane proximal regions that are densely packed beneath the lower segment of the S1-S4 sensor domain. Studies indicate that this part of the channel may contain residues that form a water-accessible cavity that undergoes changes in solvation during channel gating. We identified conserved polar residues facing the putative lower crevice of the sensor domain that were crucial determinants of the electrophilic, voltage, and calcium sensitivity of the TRPA1 channel. This part of the sensor may also comprise a domain capable of binding to membrane phosphoinositides through which gating of the channel is regulated in a state-dependent manner.

• MeSH
• alosterická regulace MeSH
• gating iontového kanálu * MeSH
• HEK293 buňky MeSH
• kationtový kanál TRPA1 chemie   fyziologie   MeSH
• konformace proteinů MeSH
• lidé MeSH
• membránové potenciály * MeSH
• molekulární modely MeSH
• mutace MeSH
• mutageneze cílená MeSH
• proteinové domény MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie MeSH
• vápník metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The transient receptor potential vanilloid 3 (TRPV3) channel is a Ca2+-permeable thermosensitive ion channel widely expressed in keratinocytes, where together with epidermal growth factor receptor (EGFR) forms a signaling complex regulating epidermal homeostasis. Proper signaling through this complex is achieved and maintained via several pathways in which TRPV3 activation is absolutely required. Results of recent studies have suggested that low-level constitutive activity of TRPV3 induces EGFR-dependent signaling that, in turn, amplifies TRPV3 via activation of the mitogen-activated protein kinase ERK in a positive feedback loop. Here, we explored the molecular mechanism that increases TRPV3 activity through EGFR activation. We used mutagenesis and whole-cell patch clamp experiments on TRPV3 channels endogenously expressed in an immortalized human keratinocyte cell line (HaCaT) and in transiently transfected HEK293T cells and found that the sensitizing effect of EGFR on TRPV3 is mediated by ERK. We observed that ERK-mediated phosphorylation of TRPV3 alters its responsiveness to repeated chemical stimuli. Among several putative ERK phosphorylation sites, we identified threonine 264 in the N-terminal ankyrin repeat domain as the most critical site for the ERK-dependent modulation of TRPV3 channel activity. Of note, Thr264 is in close vicinity to a structurally and functionally important TRPV3 region comprising an atypical finger 3 and oxygen-dependent hydroxylation site. In summary, our findings indicate that Thr264 in TRPV3 is a key ERK phosphorylation site mediating EGFR-induced sensitization of the channel to stimulate signaling pathways involved in regulating skin homeostasis.

• MeSH
• epidermální růstový faktor metabolismus   MeSH
• erbB receptory agonisté   metabolismus   MeSH
• fosforylace účinky léků   MeSH
• HEK293 buňky MeSH
• interakční proteinové domény a motivy MeSH
• kationtové kanály TRPV agonisté   chemie   genetika   metabolismus   MeSH
• keratinocyty účinky léků   enzymologie   metabolismus   MeSH
• lidé MeSH
• MAP kinasový signální systém * účinky léků   MeSH
• metoda terčíkového zámku MeSH
• mitogenem aktivovaná proteinkinasa 3 chemie   genetika   metabolismus   MeSH
• modulátory membránového transportu farmakologie   MeSH
• monoterpeny farmakologie   MeSH
• mutace MeSH
• mutageneze cílená MeSH
• posttranslační úpravy proteinů účinky léků   MeSH
• rekombinantní proteiny chemie   metabolismus   MeSH
• sloučeniny boru farmakologie   MeSH
• threonin metabolismus   MeSH
• transformované buněčné linie MeSH
• upregulace * účinky léků   MeSH
• zelené fluorescenční proteiny genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH