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The agonist binding site of ATP-gated P2X receptors is distinct from other ATP-binding proteins. Mutagenesis on P2X(1) receptors of conserved residues in mammalian P2X receptors has established the paradigm that three lysine residues, as well as FT and NFR motifs, play an important role in mediating ATP action. In this study we have determined whether(More)
At the majority of mutants in the region Glu181-Val200 incorporating a conserved AsnPheThrPhiPhixLys motif cysteine substitution had no effect on sensitivity to ATP, partial agonists, or methanethiosulfonate (MTS) compounds. For the F185C mutant the efficacy of partial agonists was reduced by approximately 90% but there was no effect on ATP potency or the(More)
P2X receptors for adenosine tri-phosphate (ATP) are a distinct family of ligand-gated cation channels with two transmembrane domains, intracellular amino and carboxy termini and a large extracellular ligand binding loop. Seven genes (P2X(1-7)) have been cloned and the channels form as either homo or heterotrimeric channels giving rise to a wide range of(More)
Degenerate PCR was used to amplify DNAs encoding members of the P2Y receptor family from rat brain RNA. A full-length sequence obtained for one novel clone (R5) contained an intronless open reading frame that encoded a polypeptide of 361 amino acids, sharing 84% sequence identity with the human P2Y4 receptor. When R5 was stably expressed in Jurkat cells,(More)
P2X receptors for extracellular ATP are a distinct family of ligand-gated cation channels involved in physiological processes ranging from synaptic transmission to muscle contraction. Common ATP binding motifs are absent from P2X receptors, and the extent of the agonist binding site is unclear. We used cysteine-scanning mutagenesis, radiolabeled 2-azido ATP(More)
The role of conserved polar glutamine, asparagine and threonine residues in the large extracellular loop, and glycosylation, to agonist action at human P2X1 receptors was tested by generating alanine substitution mutants. For the majority of mutants (Q56A, Q95A, T104A, T109A, Q112A, Q114A, T146A, N153A, T158A, N184A, N191A, N242A, N300A) alanine(More)
P2X receptors for ATP have a wide range of physiological roles and comprise a structurally distinct family of ligand-gated trimeric ion channels. The crystal structure of a P2X4 receptor, in combination with mutagenesis studies, has provided a model of the intersubunit ATP-binding sites and identified an extracellular lateral portal, adjacent to the(More)
Glycine residues can introduce flexibility in proteins, give rise to turns and breaks in secondary structure and are key components of some nucleotide binding motifs. In the P2X receptor extracellular ATP binding domain, 11 glycine residues are completely conserved and an additional five are conserved in at least five of the seven family members. We have(More)
P2X receptors for ATP are expressed throughout the body and mediate a multitude of functions, including muscle contraction, neuronal excitability and bone formation. In the mid-1990s seven genes encoding P2X receptors (P2X(1-7)) were identified. These receptors comprised a novel family of ligand-gated ion channels with subunits that possessed intracellular(More)
P2X1 receptors are ATP-gated ion channels expressed by smooth muscle and blood cells. Carboxyl-terminally His-FLAG-tagged human P2X1 receptors were stably expressed in HEK293 cells and co-purified with cytoskeletal proteins including actin. Disruption of the actin cytoskeleton with cytochalasin D inhibited P2X1 receptor currents with no effect on the time(More)