9 research outputs found
Richesses invisibles / Bruno Ory-Lavollée
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Specific alterations in the levels of N-acetyl-aspartyl-glutamate in the nervous system of the dystrophic mouse
Quantitation of N-acetyl-aspartyl-glutamate in microdissected rat brain nuclei and peripheral tissues: findings with a novel liquid phase radioimmunoassay
Differential responsiveness of the rat dorsal and median raphe 5-HT systems to 5-HT1 receptor agonists andp-chloroamphetamine
Co-localization of N-acetyl-aspartyl-glutamate in central cholinergic, noradrenergic, and serotonergic neurons
N-Acetylaspartylglutamate Synthetase II Synthesizes N-Acetylaspartylglutamylglutamate
N-Acetylaspartylglutamate (NAAG) is found at high concentrations in the vertebrate nervous system. NAAG is an agonist at group II metabotropic glutamate receptors. In addition to its role as a neuropeptide, a number of functions have been proposed for NAAG, including a role as a non-excitotoxic transport form of glutamate and a molecular water pump. We recently identified a NAAG synthetase (now renamed NAAG synthetase I, NAAGS-I), encoded by the ribosomal modification protein rimK-like family member B (Rimklb) gene, as a member of the ATP-grasp protein family. We show here that a structurally related protein, encoded by the ribosomal modification protein rimK-like family member A (Rimkla) gene, is another NAAG synthetase (NAAGS-II), which in addition, synthesizes the N-acetylated tripeptide N-acetylaspartylglutamylglutamate (NAAG2). In contrast, NAAG2 synthetase activity was undetectable in cells expressing NAAGS-I. Furthermore, we demonstrate by mass spectrometry the presence of NAAG2 in murine brain tissue and sciatic nerves. The highest concentrations of both, NAAG2 and NAAG, were found in sciatic nerves, spinal cord, and the brain stem, in accordance with the expression level of NAAGS-II. To our knowledge the presence of NAAG2 in the vertebrate nervous system has not been described before. The physiological role of NAAG2, e.g. whether it acts as a neurotransmitter, remains to be determined