Structure and expression of the glycine cleavage system in rat central nervous system

Yoshiyuki Sakata, Yuji Owada, Kohji Sato, Kanako Kojima, Kinya Hisanaga, Toshikatsu Shinka, Yoichi Suzuki, Yoko Aoki, Jo Satoh, Hisatake Kondo, Yoichi Matsubara, Shigeo Kure

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

The glycine cleavage system (GCS) is a mitochondrial multienzyme system consisting of four individual proteins, three specific components (P-, T-, and H-proteins) and one house-keeping enzyme, dihydrolipoamide dehydrogenase. Inherited deficiency of the GCS causes nonketotic hyperglycinemia (NKH), an inborn error of glycine metabolism. NKH is characterized by massive accumulation of glycine in serum and cerebrospinal fluids and severe neuronal dysfunction in neonates. To elucidate the neuropathogenesis of NKH, we cloned cDNAs encoding three specific components of the GCS and studied the gene expression in rat central nervous system. P-, T-, and H-protein cDNAs encoded 1024, 403, and 170 amino acids, respectively. In situ hybridization analysis revealed that P-protein mRNA was expressed mainly in glial-like cells, including Bergmann glias in the cerebellum, while T- and H-protein mRNAs were detected in both glial-like cells and neurons. T- and H-protein mRNAs, but not P-protein mRNA, were expressed in the spinal cord. Primary astrocyte cultures established from cerebral cortex had higher GCS activities than hepatocytes whereas those from spinal cord expressed only H-protein mRNA and had no enzymatic activity. An important role of glycine as inhibitory neurotransmitter has been established in the brainstem and spinal cord and another role of glycine as an excitation modulator of N-methyl-D-aspartate receptor is suggested in the hippocampus, cerebral cortex, olfactory bulbus, and cerebellum. Our results suggest that the GCS plays a major role in the forebrain and cerebellum rather than in the spinal cord, and that N-methyl-D-aspartate receptor may participate in neuropathogenesis of NKH.

Original languageEnglish
Pages (from-to)119-130
Number of pages12
JournalMolecular Brain Research
Volume94
Issue number1-2
DOIs
Publication statusPublished - 2001 Oct 19

Keywords

  • Astrocyte culture
  • In situ hybridization
  • Inhibitory glycine receptor
  • N-Methyl-D-aspartate receptor
  • Nonketotic hyperglycinemia
  • cDNA cloning

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience

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