The top 20 dopamine transporter mutants: structure-function relationships and cocaine actions

Area of Science:

• Neuroscience
• Molecular Biology
• Pharmacology

Background:

• The dopamine transporter (DAT) is a key target for understanding cocaine's rewarding effects.
• Previous research elucidated DAT amino acid sequences, motivating the search for selective DAT inhibitors as potential anticocaine medications.

Purpose of the Study:

• To investigate structure-function relationships of cocaine/DAT interactions using site-directed mutagenesis.
• To identify specific DAT mutations that selectively reduce cocaine analog affinity while sparing dopamine affinity.

Main Methods:

• Characterization of over 100 single- and multiple amino acid substitution mutations in the dopamine transporter (DAT).
• Selection and analysis of the 20 most informative cocaine-analog selective DAT mutants.
• Comparison of mutation locations across DAT domains and conservation in the serotonin transporter (SERT).

Main Results:

• Identified 20 DAT mutants that selectively reduce affinity for cocaine analogs but not dopamine.
• Mutations are located in various DAT domains, often clustered near transmembrane helices.
• Many identified mutations are conserved in the serotonin transporter (SERT), suggesting a shared binding mechanism.

Conclusions:

• Specific regions of DAT directly or indirectly participate in the selective recognition of cocaine analogs.
• These findings support the development of novel cocaine antagonists that spare dopamine and serotonin.
• The study provides a foundation for creating combined DAT/SERT disinhibitors for therapeutic use.