This Special Issue of International Journal of Molecular Sciences (IJMS) contains 7 reviews and 12 original research papers written by a panel of experts who highlight recent advances in molecular structure and cellular function of purinergic P2 receptors[...].
Purinergic P2X receptors represent a novel structural type of ligand-gated ion channels activated by extracellular ATP. So far, seven P2X receptor subunits have been found in excitable as well as non-excitable tissues. Little is known about their structure, mechanism of channel opening, localization, and role in the central nervous system. The aim of this work is to summarize recent investigations and describe our contribution to elucidating the structure of the ATP binding site and transmembrane domains of the P2X receptor, we also discuss the expression and physiological roles played by the ATP and P2X receptors in the anterior pituitary and hypothalamus.
- MeSH
- adenosintrifosfát metabolismus MeSH
- gonadotropní buňky metabolismus MeSH
- hypofýza metabolismus MeSH
- hypothalamus metabolismus MeSH
- ivermektin chemie farmakologie MeSH
- kvarterní struktura proteinů MeSH
- lidé MeSH
- molekulární modely MeSH
- neuroglie metabolismus MeSH
- neurony metabolismus MeSH
- purinergní receptory P2 chemie účinky léků metabolismus MeSH
- sekundární struktura proteinů MeSH
- terciární struktura proteinů MeSH
- vazba proteinů MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Ivermectin (IVM), a large macrocyclic lactone, specifically enhances P2X(4) receptor-channel function by interacting with residues of transmembrane (TM) helices in the open conformation state. In this paper, we used cysteine-scanning mutagenesis of rat P2X(4)-TMs to identify and map residues of potential importance for channel gating and interaction with IVM. The receptor function was unchanged by mutations in 29 different residues, and among them, the IVM effects were altered in Gln(36), Leu(40), Val(43), Val(47), Trp(50), Asn(338), Gly(342), Leu(346), Ala(349), and Ile(356) mutants. The substitution-sensitive Arg(33) and Cys(353) mutants could also be considered as IVM-sensitive hits. The pattern of these 12 residues was consistent with helical topology of both TMs, with every third or fourth amino acid affected by substitution. These predominantly hydrophobic-nonpolar residues are also present in the IVM-sensitive Schistosoma mansoni P2X subunit. They lie on the same side of their helices and could face lipids in the open conformation state and provide the binding pocket for IVM. In contrast, the IVM-independent hits Met(31), Tyr(42), Gly(45), Val(49), Gly(340), Leu(343), Ala(344), Gly(347), Thr(350), Asp(354), and Val(357) map on the opposite side of their helices, probably facing the pore of receptor or protein and playing important roles in gating.
- MeSH
- antiparazitární látky metabolismus MeSH
- buněčné linie MeSH
- financování organizované MeSH
- gating iontového kanálu MeSH
- ivermektin metabolismus MeSH
- konformace proteinů MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- metoda terčíkového zámku MeSH
- molekulární modely MeSH
- molekulární sekvence - údaje MeSH
- mutace MeSH
- purinergní receptory P2 genetika chemie metabolismus MeSH
- purinergní receptory P2X4 MeSH
- sekvence aminokyselin MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
Ivermectin (IVM) applied extracellularly increases the sensitivity of P2X4 receptor (P2X4R) to ATP, enhances the maximum current amplitudes, and greatly prolongs the deactivation kinetics. In this manuscript, we focused on identification of receptor-specific residues responsible for IVM effects on channel gating using the wild-type rat homomeric P2X4R, several chimeric P2X2/P2X4 receptors, and single-point P2X4R-specific mutants in the ectodomain and two transmembrane domains. Experiments with chimeric receptors revealed that the Val49-Val61 but not the Val64-Tyr315 ectodomain sequence is important for the effects of IVM on channel deactivation. Receptor-specific mutations placed in the Gly29-Val61 and Asp338-Leu358 regions showed the importance of Trp50, Val60, and Val357 residues in IVM regulation of the rate of channel deactivation, but not on the maximum current amplitude. These results suggest that the transmembrane domains and the nearby ectodomain region contribute to the effects of IVM on channel deactivation.
- MeSH
- adenosintrifosfát chemie MeSH
- antiparazitární látky farmakologie MeSH
- financování organizované MeSH
- ivermektin farmakologie chemie MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- molekulární sekvence - údaje MeSH
- purinergní receptory P2 chemie MeSH
- sekvence aminokyselin MeSH
- sekvenční homologie aminokyselin MeSH
- tryptofan chemie MeSH
- valin chemie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
