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Methamphetamine‐Induced Ubiquitination and Trafficking of Dopamine Transporters
Author(s) -
Hinshaw Tyler,
Sun Haiguo,
Leussen Deborah,
Chen Rong
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1266.4
Subject(s) - dopamine transporter , methamphetamine , ubiquitin , internalization , dopamine , dopamine plasma membrane transport proteins , chemistry , dopaminergic , endocytic cycle , neurotoxicity , microbiology and biotechnology , pharmacology , biology , endocytosis , endocrinology , receptor , biochemistry , toxicity , organic chemistry , gene
The dopamine transporter (DAT) is the primary terminator of synaptic dopamine transmission by reuptake of dopamine, and is a major target for psychostimulants including cocaine and methamphetamine. DAT undergoes constitutive and stimulated endocytosis and postendocytic trafficking. It has been shown that psychostimulants cause aberrant trafficking of DAT although the mechanisms remain elusive. Posttranslational modification of transporters by ubiquitin conjugation has recently emerged as a major regulatory mechanism of internalization and intracellular sorting of transporters and receptors. However, it is unknown whether psychostimulants alter ubiquitination of DAT. Moreover, recent evidence indicates that membrane rafts play an important role in DAT trafficking and activity. Thus, the purpose of this study is to investigate the consequence of neurotoxic treatment of methamphetamine on DAT ubiquitination and localization in lipid rafts. Methods Male Sprague Dawley rats were treated with methamphetamine (7.5 mg/kg, IP, every 2 hrs for a total of 4 injections) or saline. This treatment regimen is known to induce hyperthermia which produces neurotoxicity. To prevent the effect of hyperthermia on DAT function, rats were cooled following each methamphetamine injection. Animals were sacrificed two or ten days after the treatment. Striatal tissues were immunoprecipitated with specific DAT antibody and immunoblotted with ubiquitin antibody. The localizations of striatal DAT in lipid rafts were examined using discontinuous sucrose gradient. Results Our data showed that neurotoxic doses of methamphetamine significantly enhanced DAT ubiquitination only two days after the treatment, suggesting a transient effect of methamphetamine on DAT posttranslational modification. The heightened DAT ubiquitination was not observed after 10 days, which indicate DAT ubiquitination is reversible. We also examined the changes of DAT localization in lipid rafts and non‐lipid rafts. Methamphetamine‐induced alterations in DAT ubiquitination and translocation in lipid rafts may be associated with impaired DAT activity. Support or Funding Information This project is supported by the ASPET Zannoni Summer Undergraduate Research Fellow (SURF) Individual Awards and NIH DA006634.