Dopamine transporter cysteine mutants: Second extracellular loop cysteines are required for transporter expression

Bei Wang Jia Bei Wang, A. Moriwaki, G. R. Uhl

Research output: Contribution to journalArticlepeer-review

Abstract

Studies with thiol-modifying reagents have suggested that cysteines might play important roles in the function of the dopamine transporter (DAT). To identify DAT cysteines with important thiol groups, we have studied six mutant dopamine transporters in which cysteines were replaced by alanines. Substitutions of cysteines assigned to the DAT's second putative extracellular loop-positions 180 and 189-dramatically decreased the expression of the mutant transporters. Substitutions at positions 90, 242, 305, and 345 had no significant effect in decreasing dopamine uptake, MPP+ uptake, or cocaine analogue binding. Immunostaining COS cells transfected with Cys180 and Cys169 to Ala mutants revealed reduced membrane staining and prominent staining in perinuclear regions consistent with Golgi apparatus. These results suggest that cysteines in the DAT second extracellular loop may provide sulfide residues crucial to full transporter expression, at least in part, through interference with membrane insertion. Conceivably, they might also provide the targets for the influences of thiol- modifying reagents in modifying the function of the wild-type DAT expressed in striatal membranes.

Original languageEnglish (US)
Pages (from-to)1416-1419
Number of pages4
JournalJournal of Neurochemistry
Volume64
Issue number3
StatePublished - 1995

Keywords

  • Cocaine
  • Cysteines
  • Extracellular loop
  • Parkinsonism
  • Thiol-modifying reagents

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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