The Permeabilizing ATP Receptor, P2X7

doi:10.1074/jbc.272.9.5482

The Permeabilizing ATP Receptor, P2X₇

CLONING AND EXPRESSION OF A HUMAN cDNA*

From the Geneva Biomedical Research Institute, GlaxoWellcome Research and Development, Plan-les-Ouates, 1228 Geneva, Switzerland

^‡ To whom correspondence should be addressed:
Geneva Biomedical Research Inst., GlaxoWellcome Research and Development, Plan-les-Ouates, 1228 Geneva, Switzerland.
Tel.: 41-22-706-9739; Fax: 41-22-794-6965; E-mail FAR14949{at}ggr.co.uk

Abstract

A cDNA was isolated from a human monocyte library that encodes the P2X₇ receptor; the predicted protein is 80% identical to the rat receptor. Whole cell recordings were made from human embryonic kidney cells transfected with the human cDNA and from human macrophages. Brief applications (1-3 s) of ATP and 2′,3′-(4-benzoyl)-benzoyl-ATP elicited cation-selective currents. When compared with the rat P2X₇ receptor, these effects required higher concentrations of agonists, were more potentiated by removal of extracellular magnesium ions, and reversed more rapidly on agonist removal. Longer applications of agonists permeabilized the cells, as evidenced by uptake of the propidium dye YO-PRO1, but this was less marked than for cells expressing the rat P2X₇ receptor. Expression of chimeric molecules indicated that some of the differences between the rat and human receptor could be reversed by exchanging the intracellular C-terminal domain of the proteins.

Footnotes

↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) Y09561[GenBank].
↵¹ The abbreviations used are:

rP2X₇

rat P2X₇ receptor

hP2X₇

human macrophage P2X₇ receptor

bp

base pair(s)

PCR

polymerase chain reaction

PPADS

pyridoxal 5-phosphate-6-azophenyl 2′,4′-disulfonic acid

B2ATP

2′,3′-(4-benzoyl)-benzoyl ATP.
↵² F. Rassendren and G. N. Buell, unpublished observations.
↵³ W. Stuhmer, personal communication.
- Received December 3, 1996.