Bimodal occurrence of aspartoacylase in myelin and cytosol of brain

Jianfeng Wang, Reuben Matalon, Gita Bhatia, Gusheng Wu, Hong Li, Tong Liu, Zi Hua Lu, Robert W. Ledeen

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

The growing use of N-acetylaspartate as an indicator of neuronal viability has fostered interest in the biological function(s) of this unusual amino acid derivative. In considering the various physiological roles that have been proposed for this relatively abundant molecule one is obliged to take into account its unusual metabolic compartmentalization, according to which synthesis and storage occur in the neuron and hydrolytic cleavage in the oligodendrocyte. The latter reaction, catalyzed by aspartoacylase (ASPA), produces acetyl groups plus aspartate and has been proposed to occur in both soluble and membranous subfractions of white matter. Our study supports such bimodal occurrence and we now present immunoblot, proteomic, and biochemical evidence that the membrane-bound form of ASPA is intrinsic to purified myelin membranes. This was supported by a novel TLC-based method for the assay of ASPA. That observation, together with previous demonstrations of numerous lipid-synthesizing enzymes in myelin, suggests utilization of acetyl groups liberated by myelin-localized ASPA for lipid synthesis within the myelin sheath. Such synthesis might be selective and could explain the deficit of myelin lipids in animals lacking ASPA.

Original languageEnglish (US)
Pages (from-to)448-457
Number of pages10
JournalJournal of neurochemistry
Volume101
Issue number2
DOIs
StatePublished - Apr 1 2007

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Keywords

  • Aspartoacylase
  • Axon-myelin interaction
  • Myelin
  • Myelin lipid synthesis
  • Myelin-localized enzymes
  • N-acetylaspartate
  • N-acetylaspartate assay

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Wang, J., Matalon, R., Bhatia, G., Wu, G., Li, H., Liu, T., Lu, Z. H., & Ledeen, R. W. (2007). Bimodal occurrence of aspartoacylase in myelin and cytosol of brain. Journal of neurochemistry, 101(2), 448-457. https://doi.org/10.1111/j.1471-4159.2006.04380.x