Protein kinase C stimulates the acid-sensing ion channel ASIC2a via the PDZ domain-containing protein PICK1.
Acid-sensing ion channels (ASICs) are cationic channels activated by extracellular protons. They are expressed in central and sensory neurons where they are involved in neuromodulation and in pain perception. Recently, the PDZ domain-containing protein PICK1 (protein interacting with C-kinase) has been shown to interact with ASIC1a and ASIC2a, raising the possibility that protein kinase C (PKC) could regulate ASICs. We now show that the amplitude of the ASIC2a current, which was only modestly increased ( approximately +30%) by the PKC activator 1-oleyl-2-acetyl-sn-glycerol (OAG, 50 microm) in the absence of PICK1, was strongly potentiated ( approximately +300%) in the presence of PICK1. This PICK1-dependent regulatory effect was inhibited in the presence of a PKC inhibitory peptide and required the PDZ domain of PICK1 as well as the PDZ-binding domain of ASIC2a. We have also shown the direct PICK1-dependent phosphorylation of ASIC2a by [(32)P]phosphate labeling and immunoprecipitation and identified a major phosphorylation site, (39)TIR, on the N terminus part of ASIC2a. The OAG-induced increase in ASIC2a current amplitude did not involve any change in the unitary conductance of the ASIC2a channel, whether co-expressed with PICK1 or not. These data provide the first demonstration of a regulation of ASICs by protein kinase phosphorylation and its potentiation by the partner protein PICK1.
Baron
Anne
A
Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France.
Deval
Emmanuel
E
Salinas
Miguel
M
Lingueglia
Eric
E
Voilley
Nicolas
N
Lazdunski
Michel
M
D062565:Acid Sensing Ion Channels; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002522:Chlorocebus aethiops; D003598:Cytoskeletal Proteins; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*
C568266:ASIC1 protein, human; C568267:ASIC1 protein, mouse; C112231:ASIC3 protein, human; D062565:Acid Sensing Ion Channels; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D004075:Diglycerides; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C498298:PICK1 protein, rat; C091822:Prkcabp protein, mouse; D011994:Recombinant Proteins; D015222:Sodium Channels; D015240:Phorbol 12,13-Dibutyrate; C038237:1-oleoyl-2-acetylglycerol; D011493:Protein Kinase C