The Cytolytic P 2Z Receptor for Extracellular ATP Identified as a P 2X Receptor (P2X 7 )

The P 2Z receptor is responsible for adenosine triphosphate (ATP)-dependent lysis of macrophages through the formation of membrane pores permeable to large molecules. Other ATP-gated channels, the P 2X receptors, are permeable only to small cations. Here, an ATP receptor, the P2X 7 receptor, was cloned from rat brain and exhibited both these properties. This protein is homologous to other P 2X receptors but has a unique carboxyl-terminal domain that was required for the lytic actions of ATP. Thus, the P2X 7 (or P 2Z ) receptor is a bifunctional molecule that could function in both fast synaptic transmission and the ATP-mediated lysis of antigen-presenting cells.