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Brain Res Mol Brain Res. 1999 Feb 5;64(2):246-54.

Molecular cloning, functional characterization and possible cooperativity between the murine P2X4 and P2X4a receptors.

Author information

1
Autonomic Neuroscience Institute, Royal Free and University College Medical School, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF, UK.a.townsend.nicholson@ucl.ac.uk

Abstract

We have cloned and functionally characterised the mouse orthologue of the P2X4 receptor, mP2X4, and a splice variant of this receptor, mP2X4a. mP2X4 is 388 amino acids in length and shares 94% and 87% identity with the rat and human P2X4 receptors, respectively, while mP2X4a is 361 amino acids in length and lacks a 27-amino acid region in the extracellular domain corresponding to exon 6 of the known P2X receptor gene structures. When expressed in Xenopus laevis oocytes, mP2X4 produces a rapid inward current in response to ATP with an EC50 of 1.68+/-0.2 microM, consistent with the affinity of the rat and human P2X4 receptors for ATP. This agonist response is potentiated by the P2X receptor antagonists suramin, Reactive blue 2 and, over a limited concentration range, by PPADS. Although mP2X4a forms a poorly functional homomeric receptor, it appears able to interact with the full-length mP2X4 subunit to result in a functional channel with a reduced affinity for ATP. These results suggest a possible role for splice variants of P2X receptors in the formation of functional heteromeric ion channels.

PMID:
9931497
[Indexed for MEDLINE]

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