title: Intermediate closed channel state(s) precede(s) activation in the ATP-gated P2X2 receptor.
abstract: The molecular mechanism underlying channel opening in response to agonist binding remains a challenging issue in neuroscience. In this regard, many efforts have been recently undertaken in ATP-gated P2X receptors. Among those efforts, we have provided evidence in the P2X2 receptor that tightening of ATP sites upon agonist binding induces opening of the ion channel. Here we extend our analysis to show that the sulfhydryl-reactive ATP analog 8-thiocyano-ATP (NCS-ATP), a potent P2X2 agonist, when covalently labeled in the ATP-binding site at position Leu186 likely favors the tightening mechanism, but not the channel opening mechanism. Our data predict the existence of intermediate or preactivation state(s) trapped by NCS-ATP, in which tightening of the binding site is favored while the channel is still closed. We propose that this (these) intermediate ATP-bound state(s) prime(s) channel gating in the P2X2 receptor.
authors.affiliation: Laboratoire de Biophysicochimie des Récepteurs Canaux, Conception et Application de Molécules Bioactives, CNRS UMR 7199, Faculté de Pharmacie, Université de Strasbourg, Strasbourg, France.
authors.forename: Ruotian
authors.initials: R
authors.lastname: Jiang
authors.forename: Antoine
authors.initials: A
authors.lastname: Taly
authors.forename: Damien
authors.initials: D
authors.lastname: Lemoine
authors.forename: Adeline
authors.initials: A
authors.lastname: Martz
authors.forename: Alexandre
authors.initials: A
authors.lastname: Specht
authors.forename: Thomas
authors.initials: T
authors.lastname: Grutter
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D000345:Affinity Labels; D001665:Binding Sites; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects; D009154:Mutation; D058911:Purinergic P2X Receptor Agonists / Q000494:pharmacology; D058476:Receptors, Purinergic P2X2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000345:Affinity Labels; D058911:Purinergic P2X Receptor Agonists; D058476:Receptors, Purinergic P2X2; C073140:8-thiocyano-adenosine triphosphate; D000255:Adenosine Triphosphate