P2X7 purinoceptor (IPR003050)

Short name: P2X7_purinoceptor

Overlapping homologous superfamilies

Family relationships


P2X purinoceptors are cell membrane ion channels, gated by adenosine 5'-triphosphate (ATP) and other nucleotides; they have been found to be widely expressed on mammalian cells, and, by means of their functional properties, can be differentiated into three sub-groups. The first group is almost equally well activated by ATP and its analogue alpha,betamethylene-ATP, whereas, the second group is not activated by the latter compound. A third type of receptor (also called P2Z) is distinguished by the fact that repeated or prolonged agonist application leads to the opening of much larger pores, allowing large molecules to traverse the cell membrane. This increased permeability rapidly leads to cell death, and lysis.

Molecular cloning studies have identified seven P2X receptor subtypes, designated P2X1-P2X7. These receptors are proteins that share 35-48% amino acid identity, and possess two putative transmembrane (TM) domains, separated by a long (~270 residues) intervening sequence, which is thought to form an extracellular loop. Around 1/4 of the residues within the loop are invariant between the cloned subtypes, including 10 characteristic cysteines.

Studies of the functional properties of heterologously expressed P2X receptors, together with the examination of their distribution in native tissues, suggests they likely occur as both homo- and heteromultimers in vivo [PMID: 10414359, PMID: 12270951].

This entry represents P2X7 (also known as P2Z receptor), when P2X7 receptor is expressed, it is found to have different functional properties from those of P2X1-P2X6. Key properties of the current produced are little rectification or desensitisation, and strong potentiation of responses when the concentration of extracellular Ca2+ and/or Mg2+ are reduced. It is also found to be relatively insensitive to ATP. In certain studies, prolonged activation of expressed P2X7 receptors causes cell permeabilisation, and lysis.

GO terms

Biological Process

GO:0006811 ion transport

Molecular Function

GO:0005524 ATP binding
GO:0005216 ion channel activity
GO:0001614 purinergic nucleotide receptor activity

Cellular Component

GO:0016020 membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.