| First Author | Zhou MH | Year | 2021 |
| Journal | J Neurosci | Volume | 41 |
| Issue | 30 | Pages | 6415-6429 |
| PubMed ID | 34252035 | Mgi Jnum | J:308388 |
| Mgi Id | MGI:6729133 | Doi | 10.1523/JNEUROSCI.0757-21.2021 |
| Citation | Zhou MH, et al. (2021) Protein Kinase C-Mediated Phosphorylation and alpha2delta-1 Interdependently Regulate NMDA Receptor Trafficking and Activity. J Neurosci 41(30):6415-6429 |
| abstractText | N-methyl-d-aspartate receptors (NMDARs) are important for synaptic plasticity associated with many physiological functions and neurologic disorders. Protein kinase C (PKC) activation increases the phosphorylation and activity of NMDARs, and alpha2delta-1 is a critical NMDAR-interacting protein and controls synaptic trafficking of NMDARs. In this study, we determined the relative roles of PKC and alpha2delta-1 in the control of NMDAR activity. We found that alpha2delta-1 coexpression significantly increased NMDAR activity in HEK293 cells transfected with GluN1/GluN2A or GluN1/GluN2B. PKC activation with phorbol 12-myristate 13-acetate (PMA) increased receptor activity only in cells coexpressing GluN1/GluN2A and alpha2delta-1. Remarkably, PKC inhibition with G6983 abolished alpha2delta-1-coexpression-induced potentiation of NMDAR activity in cells transfected with GluN1/GluN2A or GluN1/GluN2B. Treatment with PMA increased the alpha2delta-1-GluN1 interaction and promoted alpha2delta-1 and GluN1 cell surface trafficking. PMA also significantly increased NMDAR activity of spinal dorsal horn neurons and the amount of alpha2delta-1-bound GluN1 protein complexes in spinal cord synaptosomes in wild-type mice, but not in alpha2delta-1 knockout mice. Furthermore, inhibiting alpha2delta-1 with pregabalin or disrupting the alpha2delta-1-NMDAR interaction with the alpha2delta-1 C-terminus peptide abolished the potentiating effect of PMA on NMDAR activity. Additionally, using quantitative phosphoproteomics and mutagenesis analyses, we identified S929 on GluN2A and S1413 (S1415 in humans) on GluN2B as the phosphorylation sites responsible for NMDAR potentiation by PKC and alpha2delta-1. Together, our findings demonstrate the interdependence of alpha2delta-1 and PKC phosphorylation in regulating NMDAR trafficking and activity. The phosphorylation-dependent, dynamic alpha2delta-1-NMDAR interaction constitutes an important molecular mechanism of synaptic plasticity.SIGNIFICANCE STATEMENT A major challenge in studies of protein phosphorylation is to define the functional significance of each phosphorylation event and determine how various signaling pathways are coordinated in response to neuronal activity to shape synaptic plasticity. PKC phosphorylates transporters, ion channels, and G-protein-coupled receptors in signal transduction. In this study, we showed that alpha2delta-1 is indispensable for PKC-activation-induced surface and synaptic trafficking of NMDARs, whereas the alpha2delta-1-NMDAR interaction is controlled by PKC-induced phosphorylation. Our findings reveal that alpha2delta-1 mainly functions as a phospho-binding protein in the control of NMDAR trafficking and activity. This information provides new mechanistic insight into the reciprocal roles of PKC-mediated phosphorylation and alpha2delta-1 in regulating NMDARs and in the therapeutic actions of gabapentinoids. |
