Campbell, N.G., Shekar, A., Aguilar, J.I., Peng, D., Navratna, V., Yang, D., Morley, A.N., Duran, A.M., Galli, G., O'Grady, B., Ramachandran, R., Sutcliffe, J.S., Sitte, H.H., Erreger, K., Meiler, J., Stockner, T., Bellan, L.M., Matthies, H.J.G., Gouaux, E., Mchaourab, H.S., Galli, A. (2019). Structural, functional, and behavioral insights of dopamine dysfunction revealed by a deletion in SLC6A3.  Proc. Natl. Acad. Sci. U.S.A. 116(9): 3853--3862.

FBrf0241664

Research paper

The human dopamine (DA) transporter (hDAT) mediates clearance of DA. Genetic variants in hDAT have been associated with DA dysfunction, a complication associated with several brain disorders, including autism spectrum disorder (ASD). Here, we investigated the structural and behavioral bases of an ASD-associated in-frame deletion in hDAT at N336 (∆N336). We uncovered that the deletion promoted a previously unobserved conformation of the intracellular gate of the transporter, likely representing the rate-limiting step of the transport process. It is defined by a "half-open and inward-facing" state (HOIF) of the intracellular gate that is stabilized by a network of interactions conserved phylogenetically, as we demonstrated in hDAT by Rosetta molecular modeling and fine-grained simulations, as well as in its bacterial homolog leucine transporter by electron paramagnetic resonance analysis and X-ray crystallography. The stabilization of the HOIF state is associated both with DA dysfunctions demonstrated in isolated brains of Drosophila melanogaster expressing hDAT ∆N336 and with abnormal behaviors observed at high-time resolution. These flies display increased fear, impaired social interactions, and locomotion traits we associate with DA dysfunction and the HOIF state. Together, our results describe how a genetic variation causes DA dysfunction and abnormal behaviors by stabilizing a HOIF state of the transporter.

PMC6397532 (PMC) (EuropePMC)