Dopamine Transporter Activity Is Modulated by α-Synuclein

Brittany Butler,Kaustuv Saha,Tanu Rana,Jonas P Becker,Danielle Sambo,Paran Davari,J Shawn Goodwin,Habibeh Khoshbouei

doi:10.1074/jbc.m115.691592

Abstract

The duration and strength of the dopaminergic signal are regulated by the dopamine transporter (DAT). Drug addiction and neurodegenerative and neuropsychiatric diseases have all been associated with altered DAT activity. The membrane localization and the activity of DAT are regulated by a number of intracellular proteins. α-Synuclein, a protein partner of DAT, is implicated in neurodegenerative disease and drug addiction. Little is known about the regulatory mechanisms of the interaction between DAT and α-synuclein, the cellular location of this interaction, and the functional consequences of this interaction on the basal, amphetamine-induced DAT-mediated dopamine efflux, and membrane microdomain distribution of the transporter. Here, we found that the majority of DAT·α-synuclein protein complexes are found at the plasma membrane of dopaminergic neurons or mammalian cells and that the amphetamine-mediated increase in DAT activity enhances the association of these proteins at the plasma membrane. Further examination of the interaction of DAT and α-synuclein revealed a transient interaction between these two proteins at the plasma membrane. Additionally, we found DAT-induced membrane depolarization enhances plasma membrane localization of α-synuclein, which in turn increases dopamine efflux and enhances DAT localization in cholesterol-rich membrane microdomains.

Highlights

dopamine transporter (DAT) regulates dopamine neurotransmission in the brain
We found that the majority of DAT1⁄7␣-synuclein protein complexes are found at the plasma membrane of dopaminergic neurons or mammalian cells and that the amphetamine-mediated increase in DAT activity enhances the association of these proteins at the plasma membrane
Humans and rodents exposed to amphetamines have increased levels of ␣-synuclein in the striatum, which is a brain region with the highest level of dopamine transporter [19]

Summary

Introduction

Results: ␣-Synuclein influences DA efflux and membrane microdomain distribution of DAT. Conclusion: DAT activation recruits ␣-synuclein to the membrane, which in turn influences dopamine neurotransmission. Drug addiction and neurodegenerative and neuropsychiatric diseases have all been associated with altered DAT activity. ␣-Synuclein, a protein partner of DAT, is implicated in neurodegenerative disease and drug addiction. Little is known about the regulatory mechanisms of the interaction between DAT and ␣-synuclein, the cellular location of this interaction, and the functional consequences of this interaction on the basal, amphetamine-induced DAT-mediated dopamine efflux, and membrane microdomain distribution of the transporter. We found that the majority of DAT1⁄7␣-synuclein protein complexes are found at the plasma membrane of dopaminergic neurons or mammalian cells and that the amphetamine-mediated increase in DAT activity enhances the association of these proteins at the plasma membrane. We found DAT-induced membrane depolarization enhances plasma membrane localization of ␣-synuclein, which in turn increases dopamine efflux and enhances DAT localization in cholesterol-rich membrane microdomains

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