Protein Kinase C Stimulates the Acid-sensing Ion Channel ASIC2a via the PDZ Domain-containing Protein PICK1

Anne Baron,Emmanuel Deval,Miguel Salinas,Eric Lingueglia,Nicolas Voilley,Michel Lazdunski

doi:10.1074/jbc.m208848200

Anne Baron, Emmanuel Deval + Show 4 more

https://doi.org/10.1074/jbc.m208848200

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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.

Highlights

In sensory and central neurons, Hϩ-activated cation currents flowing through acid-sensing ionic channels (ASICs)1 have been widely recorded, showing functional and pharmacological properties depending on the homomeric or heteromeric association of different Acid-sensing ion channels (ASICs) subunits [1, 2]
The ASIC2a current density was not increased in the presence of PICK1 (Fig. 2B), unlike the situation observed with ASIC3 after its interaction with another PDZ domain-containing partner protein CIPP [29]
ASIC2a Current—When 50 ␮M OAG, the cell-permeable analog of the endogenous protein kinase C (PKC) activator diacylglycerol, was applied extracellularly, it induced a 1.35 Ϯ 0.08-fold (n ϭ 12) increase of ASIC2a current amplitude (Fig. 3, A (E) and B), significantly different from the basal variation of ASIC2a current amplitude (0.98 Ϯ 0.08, n ϭ 5, Fig. 3B, bar 1, ૾; p Ͻ 0.05). This effect was strongly potentiated in the presence of PICK1 with a 3.90 Ϯ 0.54-fold increase (n ϭ 20) of the ASIC2a current induced by OAG (50 ␮M) (Fig. 3, A (G) and B)

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Introduction

In sensory and central neurons, Hϩ-activated cation currents flowing through acid-sensing ionic channels (ASICs)1 have been widely recorded, showing functional and pharmacological properties depending on the homomeric or heteromeric association of different ASIC subunits [1, 2]. 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.

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