Dopamine uptake and cocaine binding mechanisms: The involvement of charged amino acids from the transmembrane domains of the human dopamine transporter

Dalit E. Dar, Thomas G. Metzger, David J. Vandenbergh, George R. Uhl

Research output: Contribution to journalArticle

Abstract

The wild type human dopamine transporter (DAT) and five DAT mutants were transfected into COS-7 cells and their ability to uptake dopamine or to bind cocaine was examine three days later. In each mutant, a single charged amino acid, located in areas that initial hydrophobic analysis had indicated were DAT transmembrane domains was substituted by alanine. Mutants used in this study were lysines 257 and 525 (termed K257A and K525A), arginines 283 and 521 (termed R283A and R521A), and glutamate 491 (termed E491A). Dopamine affinity was significantly enhanced in the K257A and R283A mutants, and the IC50 for displacement of the radioactive cocaine analog 2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (CFT) by cocaine was significantly elevated in the E491A mutant. All mutants displayed a reduction or complete loss of the maximal velocity (Vm) of dopamine transport.

Original languageEnglish (US)
Pages (from-to)43-47
Number of pages5
JournalEuropean Journal of Pharmacology
Volume538
Issue number1-3
DOIs
StatePublished - May 24 2006
Externally publishedYes

Keywords

  • Charged amino acid
  • Cocaine
  • Dopamine transporter
  • Glutamate
  • Mutant

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Pharmacology

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