Localization of N-glycosylation sites and functional role of the carbohydrate units of GLAST-1, a cloned rat brain L-glutamate/L-aspartate transporter.

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  • Author(s): Conradt M;Conradt M; Storck T; Stoffel W
  • Source:
    European journal of biochemistry [Eur J Biochem] 1995 May 01; Vol. 229 (3), pp. 682-7.
  • Publication Type:
    Journal Article; Research Support, Non-U.S. Gov't
  • Language:
    English
  • Additional Information
    • Source:
      Publisher: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies Country of Publication: England NLM ID: 0107600 Publication Model: Print Cited Medium: Print ISSN: 0014-2956 (Print) Linking ISSN: 00142956 NLM ISO Abbreviation: Eur J Biochem Subsets: MEDLINE
    • Publication Information:
      Publication: -2004: Oxford, UK : Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
      Original Publication: Berlin, New York, Springer.
    • Subject Terms:
      Carbohydrate Metabolism*; Brain/*metabolism ; Carrier Proteins/*physiology ; Glycoproteins/*physiology; Amino Acid Transport System X-AG ; Animals ; Asparagine ; Base Sequence ; Carrier Proteins/chemistry ; Carrier Proteins/genetics ; Cloning, Molecular ; DNA Primers/chemistry ; Gene Expression ; Glycoproteins/chemistry ; Glycoproteins/genetics ; Glycosylation ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Mutation ; Oocytes/metabolism ; Precipitin Tests ; Rats ; Xenopus laevis
    • Abstract:
      The L-glutamate transporter GLAST-1 belongs to the newly discovered family of Na(+)-dependent, high-affinity glutamate transporters, which are involved in the regulation of synaptic excitatory neurotransmitter concentration in mammalian brain. The members of this family have a similar topological organisation with at least six transmembrane helices (TMHs) and two putative N-glycosylation sites located in the extracellular loop connecting TMH 3 and TMH 4. Besides these two conserved N-glycosylation motifs at Asn206 and Asn216, GLAST-1 possesses an additional one at Asn35. The putative N-glycosylation consensus motifs (Asn-Xaa-Ser/Thr) were deleted by replacement of Asn206 and/or Asn216 by Thr using site-directed mutagenesis (mutants N206T, N216T and N206,216T). The cDNAs encoding wild-type GLAST-1 and the three glycosylation-defective transport proteins were expressed in the Xenopus laevis oocyte system. Immunoprecipitation of the [35S]methionine-labeled and glycopeptidase-F-treated transporter molecules indicates that GLAST-1 is glycosylated at Asn206 and Asn216, whereas Asn35 remains unglycosylated. To assess a possible functional role of the two glycosylation sites wild-type and glycosylation-deficient GLAST-1 were expressed in Xenopus oocytes and characterized functionally by using the whole-cell voltage-clamp technique. The results prove that N-glycosylation has no impact on the transport activity of GLAST-1.
    • Accession Number:
      0 (Amino Acid Transport System X-AG)
      0 (Carrier Proteins)
      0 (DNA Primers)
      0 (Glycoproteins)
      7006-34-0 (Asparagine)
    • Publication Date:
      Date Created: 19950501 Date Completed: 19950627 Latest Revision: 20190620
    • Publication Date:
      20231215
    • Accession Number:
      10.1111/j.1432-1033.1995.tb20514.x
    • Accession Number:
      7758463