title: P2X2 and P2X5 subunits define a new heteromeric receptor with P2X7-like properties.
abstract: Ligand-gated ion channels are prototypic oligomeric membrane proteins whose stoichiometry determines their functional properties and subcellular localization. Deciphering the quaternary structure of such protein complexes is an arduous task and usually requires the combination of multiple approaches. ATP-gated P2X receptors are formed by the association of three subunits, but the quaternary arrangement of the seven P2X subunits at the plasma membrane remains poorly characterized. By combining bioluminescence resonance energy transfer, bifunctional fluorescence complementation and protein biochemistry, we developed an experimental approach that allows precise determination of rat P2X receptor quaternary assembly. We found that P2X5 subunits associate with P2X1, P2X2, and P2X4 subunits. We demonstrate that P2X5 and P2X2 subunits interact to form as yet uncharacterized heteromeric receptors with alternate stoichiometries, both present at the plasma membrane. P2X2/5 receptors display functional properties such as pore dilatation, membrane blebbing, and phosphatidylserine exposure that were previously thought to be characteristic hallmarks of the P2X7 receptor. In mouse, P2X2 and P2X5 subunits colocalize and physically interact in specific neuronal populations suggesting that other P2X receptors might contribute to cellular responses typically attributed to P2X7 receptor.
authors.affiliation: Universités de Montpellier, Montpellier, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Compan
authors.forename: Lauriane
authors.initials: L
authors.lastname: Ulmann
authors.forename: Olga
authors.initials: O
authors.lastname: Stelmashenko
authors.forename: Jean
authors.initials: J
authors.lastname: Chemin
authors.forename: Séverine
authors.initials: S
authors.lastname: Chaumont
authors.forename: Francois
authors.initials: F
authors.lastname: Rassendren
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D001583:Benzoxazoles / Q000378:metabolism; D060807:Bioluminescence Resonance Energy Transfer Techniques / Q000379:methods; D001921:Brain / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005727:Ganglia, Spinal / Q000166:cytology; D057809:HEK293 Cells; D006801:Humans; D047468:Immunoprecipitation; D008164:Luminescent Proteins / Q000235:genetics; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics; D051379:Mice; D016297:Mutagenesis, Site-Directed / Q000379:methods; D009154:Mutation / Q000235:genetics; D018408:Patch-Clamp Techniques; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D058905:Purinergic Agents / Q000494:pharmacology; D011806:Quinolinium Compounds / Q000378:metabolism; D058476:Receptors, Purinergic P2X2 / Q000235:genetics / Q000378:metabolism*; D058485:Receptors, Purinergic P2X5 / Q000235:genetics / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7 / Q000502:physiology*; D014162:Transfection; D014741:Video Recording; D014982:Xenopus laevis
chemical_list: D017304:Annexin A5; D001583:Benzoxazoles; D008164:Luminescent Proteins; D021122:Protein Subunits; D058905:Purinergic Agents; D011806:Quinolinium Compounds; D058476:Receptors, Purinergic P2X2; D058485:Receptors, Purinergic P2X5; D058486:Receptors, Purinergic P2X7; C089813:YO-PRO 1; C022571:adenosine 5'-O-(3-thiotriphosphate); C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D000255:Adenosine Triphosphate