title: Topological analysis of the ATP-gated ionotropic [correction of ionotrophic] P2X2 receptor subunit.
abstract: We investigated the transmembrane topology of the P2X2 receptor subunit expressed in HEK 293 cells. Initial studies using two P2X subunits expressed in tandem indicated that the amino- and carboxy-termini are on the same side of the membrane. Immunofluorescence studies showed the cytoplasmic orientation of the amino- and carboxy-termini. Finally, N-glycosylation scanning mutagenesis revealed that reporter sites inserted into the central loop, but not those in the amino- or carboxy-terminal regions, were glycosylated, thus suggesting an extracellular placement for that domain. Our results support a two-transmembrane arrangement for P2X receptors with intracellular amino- and carboxy-termini.
authors.affiliation: Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, MO 63104, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Torres
authors.forename: T M
authors.initials: TM
authors.lastname: Egan
authors.forename: M M
authors.initials: MM
authors.lastname: Voigt
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D018076:DNA, Complementary; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D011487:Protein Conformation; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D058476:Receptors, Purinergic P2X2
chemical_list: D018076:DNA, Complementary; D008565:Membrane Proteins; C546401:P2RX2 protein, human; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate