Proapoptotic plasma membrane pore: P2X(7) receptor

ATP is not only the universal currency of energy metabolism but also a ubiq uitous extracellular messenger. Among its many effects the ability to trigg er cell death has attracted considerable interest. The plasma membrane rece ptor responsible for this effect has been cloned and shown to belong to the P2X family (P2X(7)). The P2X(7) receptor is a plasma membrane ion channel that, under certain conditions, can grow to form a nonselective pore. Prolo nged opening of this receptor is a potent apoptotic stimulus for several ce ll types. The main mechanism responsible for this deadly effect seems to re side in the drastic upset of the intracellular concentration of Ca2+ as wel l as K+. The loss of intracellular K+ has a permissive effect on the progre ssion of apoptosis by causing the activation of key proapoptotic enzymes su ch as caspase 3 and NUC18. The P2X(7) receptor could be an interesting mode l for the study of apoptotic pathways triggered by plasma membrane channels . Drug Dev. Res. 52:571-578, 2001. (C) 2001 Wiley-Liss, Inc.