Signaling microdomains define the specificity of receptor-mediated InsP(3) pathways in neurons.
M(1) muscarinic (M(1)AChRs) and B(2) bradykinin (B(2)Rs) receptors are two PLCbeta-coupled receptors that mobilize Ca(2+) in nonexcitable cells. In many neurons, however, B(2)Rs but not M(1)AChRs mobilize intracellular Ca(2+). We have studied the membrane organization and dynamics underlying this coupling specificity by using Trp channels as biosensors for real-time detection of PLCbeta products. We found that, in sympathetic neurons, although both receptors rapidly produced DAG and InsP(3) as messengers, only InsP(3) formed by B(2)Rs has the ability to activate IP(3)Rs. This exclusive coupling results from spatially restricted complexes linking B(2)Rs to IP(3)Rs, a missing partnership for M(1)AChRs. These complexes allow fast and localized rises of InsP(3), necessary to activate the low-affinity neuronal IP(3)R. Thus, these signaling microdomains are of critical importance for the induction of selective responses, discriminating proinflammatory information associated with B(2)Rs from cholinergic neurotransmission.
Delmas
Patrick
P
Wellcome Laboratory for Molecular Pharmacology, Department of Pharmacology, University College London, Gower Street, WC1E 6BT, London, United Kingdom. delmas@irlnb.cnrs-mrs.fr
Wanaverbecq
Nicolas
N
Abogadie
Fe C
FC
Mistry
Mohini
M
Brown
David A
DA
D000199:Actins / Q000502:physiology; D000818:Animals; D015374:Biosensing Techniques; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism / Q000502:physiology*; D002147:Calmodulin / Q000502:physiology; D003599:Cytoskeleton / Q000502:physiology; D004075:Diglycerides / Q000096:biosynthesis; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D054799:Phospholipase C beta; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043782:Receptor, Bradykinin B2; D043643:Receptor, Muscarinic M1; D018002:Receptors, Bradykinin / Q000502:physiology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology*; D011976:Receptors, Muscarinic / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D050052:TRPC Cation Channels; D010738:Type C Phospholipases / Q000378:metabolism
D000199:Actins; D015220:Calcium Channels; D002147:Calmodulin; D004075:Diglycerides; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes; D043782:Receptor, Bradykinin B2; D043643:Receptor, Muscarinic M1; D018002:Receptors, Bradykinin; D018160:Receptors, Cytoplasmic and Nuclear; D011976:Receptors, Muscarinic; D050052:TRPC Cation Channels; D015544:Inositol 1,4,5-Trisphosphate; C087857:protein kinase C gamma; D011493:Protein Kinase C; D010738:Type C Phospholipases; D054799:Phospholipase C beta; D002118:Calcium