Signaling at purinergic P2X receptors.
P2X receptors are membrane cation channels gated by extracellular ATP. Seven P2X receptor subunits (P2X(1-7)) are widely distributed in excitable and nonexcitable cells of vertebrates. They play key roles in inter alia afferent signaling (including pain), regulation of renal blood flow, vascular endothelium, and inflammatory responses. We summarize the evidence for these and other roles, emphasizing experimental work with selective receptor antagonists or with knockout mice. The receptors are trimeric membrane proteins: Studies of the biophysical properties of mutated subunits expressed in heterologous cells have indicated parts of the subunits involved in ATP binding, ion permeation (including calcium permeability), and membrane trafficking. We review our current understanding of the molecular properties of P2X receptors, including how this understanding is informed by the identification of distantly related P2X receptors in simple eukaryotes.
Surprenant
Annmarie
A
Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom. a.surprenant@manchester.ac.uk
North
R Alan
RA
D000255:Adenosine Triphosphate / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D002490:Central Nervous System / Q000502:physiology; D006801:Humans; D007473:Ion Channels / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D018048:Receptors, Purinergic P2 / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D058469:Receptors, Purinergic P2X; D015398:Signal Transduction / Q000502:physiology*
D007473:Ion Channels; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D000255:Adenosine Triphosphate