Nanoscopic dopamine transporter distribution and conformation are inversely regulated by excitatory drive and D2-autoreceptor activity

• DOI: 10.1101/2021.03.09.434538
• Publication Date: 2021-03-10T22:55:16Z
• Authors: Matthew D. Lycas; Aske L. Ejdrup; Andreas T. Sørensen; Nicolai O. Haahr; Søren H. Jørgensen; Daryl A. Guthrie; Jonatan F. Støier; Christian Werner; Amy Hauck Newman; Markus Sauer; Freja Herborg; Ulrik Gether
• Keywords: 0301 basic medicine; Dopamine Plasma Membrane Transport Proteins; synaptic architecture; volume transmission; Neuroscience [CP]; neurotransmitter transporters; Qa-SNARE Proteins; Dopamine; Dopaminergic Neurons; Phosphatidylinositols; nanodomains; Article; Clathrin; Mice; 03 medical and health sciences; PIP2; CP: Neuroscience; super-resolution microscopy; Animals; dopamine transporter; fluorescent cocaine analogues; dopamine receptors; Autoreceptors

SUMMARYThe nanoscopic organization and regulation of individual molecular components in presynaptic varicosities of neurons releasing modulatory volume neurotransmitters like dopamine (DA) remain largely elusive. Here we show by application of several super-resolution microscopy techniques to cultured neurons and mouse striatal slices, that the dopamine transporter (DAT), a key protein in varicosities of dopaminergic neurons, exists in the membrane in dynamic equilibrium between an inward-facing nanodomain-localized and outward-facing unclustered configuration. The balance between these configurations is inversely regulated by excitatory drive and by DA D2-autoreceptor activation in manner dependent on Ca2+-influx via N-type voltage-gated Ca2+-channels. The DAT nanodomains contain tens of transporters molecules and overlap with nanodomains of PIP2 (phosphatidylinositol-4,5-bisphosphate) but show little overlap with D2-autoreceptor, syntaxin-1 and clathrin nanodomains. Summarized, the data reveal a mechanism for rapid alterations in nanoscopic DAT distribution and show a striking link of this to the conformational state of the transporter.