RT Journal Article
SR Electronic
T1 Biphasic Coupling of Neuronal Nitric Oxide Synthase Phosphorylation to the NMDA Receptor Regulates AMPA Receptor Trafficking and Neuronal Cell Death
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 3445
OP 3455
DO 10.1523/JNEUROSCI.4799-06.2007
VO 27
IS 13
A1 Gerald A. Rameau
A1 David S. Tukey
A1 Elsa D. Garcin-Hosfield
A1 Roseann F. Titcombe
A1 Charu Misra
A1 Latika Khatri
A1 Elizabeth D. Getzoff
A1 Edward B. Ziff
YR 2007
UL http://www.jneurosci.org/content/27/13/3445.abstract
AB Postsynaptic nitric oxide (NO) production affects synaptic plasticity and neuronal cell death. Ca2+ fluxes through the NMDA receptor (NMDAR) stimulate the production of NO by neuronal nitric oxide synthase (nNOS). However, the mechanisms by which nNOS activity is regulated are poorly understood. We evaluated the effect of neuronal stimulation with glutamate on the phosphorylation of nNOS. We show that, in cortical neurons, a low glutamate concentration (30 μm) induces rapid and transient NMDAR-dependent phosphorylation of S1412 by Akt, followed by sustained phosphorylation of S847 by CaMKII (calcium-calmodulin-dependent kinase II). We demonstrate that phosphorylation of S1412 by Akt is necessary for activation of nNOS by the NMDAR. nNOS mutagenesis confirms that these phosphorylations respectively activate and inhibit nNOS and, thus, transiently activate NO production. A constitutively active (S1412D), but not a constitutively repressed (S847D) nNOS mutant elevated surface glutamate receptor 2 levels, demonstrating that these phosphorylations can control AMPA receptor trafficking via NO. Notably, an excitotoxic stimulus (150 μm glutamate) induced S1412, but not S847 phosphorylation, leading to deregulated nNOS activation. S1412D did not kill neurons; however, it enhanced the excitotoxicity of a concomitant glutamate stimulus. We propose a swinging domain model for the regulation of nNOS: S1412 phosphorylation facilitates electron flow within the reductase module of nNOS, increasing nNOS sensitivity to Ca2+-calmodulin. These findings suggest a critical role for a kinetically complex and novel series of regulatory nNOS phosphorylations induced by the NMDA receptor for the in vivo control of nNOS.