Serine racemase: Activation by glutamate neurotransmission via glutamate receptor interacting protein and mediation of neuronal migration

AUTOR(ES)
FONTE

National Academy of Sciences

RESUMO

Serine racemase (SR), localized to astrocytic glia that ensheathe synapses, converts l-serine to d-serine, an endogenous ligand of the NMDA receptor. We report the activation of SR by glutamate neurotransmission involving α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors via glutamate receptor interacting protein (GRIP) and the physiologic regulation of cerebellar granule cell migration by SR. GRIP physiologically binds SR, augmenting SR activity and d-serine release. GRIP infection of neonatal mouse cerebellum in vivo enhances granule cell migration. Selective degradation of d-serine by d-amino acid oxidase and pharmacologic inhibition of SR impede migration, whereas d-serine activates the process. Thus, in neuronal migration, glutamate stimulates Bergmann glia to form and release d-serine, which, together with glutamate, activates NMDA receptors on granule neurons, chemokinetically enhancing migration.

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