Mutational effects of human dopamine transporter at tyrosine88, lysine92, and histidine547 on basal and HIV-1 Tat-inhibited dopamine transport

Sci Rep. 2019 Mar 7;9(1):3843. doi: 10.1038/s41598-019-39872-1.

Abstract

Dysregulation of dopaminergic system induced by HIV-1 Tat protein-mediated direct inhibition of the dopamine transporter (DAT) has been implicated as a mediating factor of HIV-1 associated neurocognitive disorders. We have reported that single point mutations on human DAT (hDAT) at tyrosine88 (Y88F), lysine92 (K92M), and histidine547 (H547A) differentially regulate basal dopamine uptake but diminish Tat-induced inhibition of dopamine uptake by changing dopamine transport process. This study evaluated the effects of double (Y88F/H547A) and triple (Y88F/K92M/H547A) mutations on basal dopamine uptake, Tat-induced inhibition of DAT function, and dynamic transport process. Compared to wild-type hDAT, the Vmax values of [3H]Dopamine uptake were increased by 96% in Y88F/H547A but decreased by 97% in Y88F/K92M/H547A. [3H]WIN35,428 binding sites were not altered in Y88F/H547A but decreased in Y88F/K92M/H547A. Y88F/H547A mutant attenuated Tat-induced inhibition of dopamine uptake observed in wild-type hDAT. Y88F/H547A displayed an attenuation of zinc-augmented [3H]WIN35,428 binding, increased basal dopamine efflux, and reduced amphetamine-induced dopamine efflux, indicating this mutant alters transporter conformational transitions. These findings further demonstrate that both tyrosine88 and histidine547 on hDAT play a key role in stabilizing basal dopamine transport and Tat-DAT integration. This study provides mechanistic insights into developing small molecules to block multiple sites in DAT for Tat binding.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • AIDS Dementia Complex / metabolism
  • Dopamine / metabolism
  • Dopamine Plasma Membrane Transport Proteins / genetics*
  • Dopamine Plasma Membrane Transport Proteins / metabolism
  • HIV Infections / metabolism*
  • HIV-1* / metabolism
  • Humans
  • Point Mutation / genetics*
  • tat Gene Products, Human Immunodeficiency Virus / metabolism*

Substances

  • Dopamine Plasma Membrane Transport Proteins
  • tat Gene Products, Human Immunodeficiency Virus
  • Dopamine