Histidine-419 plays a role in energy coupling in the vesicular monoamine transporter from rat

Anat Shirvan, Orly Laskar, Sonia Steiner-Mordoch, Shimon Schuldiner*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Vesicular monoamine transporters (VMAT) catalyze transport of serotonin, dopamine, epinephrine and norepinephrine into subcellular storage organelles in a variety of cells. Accumulation of the neurotransmitter depends on the proton electrochemical gradient across the organelle membrane and involves VMAT-mediated exchange of two lumenal protons with one cytoplasmic amine. It has been suggested in the past that His residues play a role in H+ movement or in its coupling to active transport in H+-symporters and antiporters. Indeed VMAT-mediated transport is inhibited by reagents specific for His residues. We have identified one His residue in VMAT1 from rat which is conserved in other vesicular neurotransmitter transporters. Mutagenesis of this His (H419) to either Arg or Cys completely inhibits [3H]serotonin and [3H]dopamine accumulation. Mutagenesis also inhibits other H+-dependent partial reactions of VMAT such as the acceleration of binding of the high affinity ligand reserpine, but does not inhibit the [3H]reserpine binding which is not dependent on H+ translocation. It is concluded that His-419 plays a role in energy coupling in r-VMAT1.

Original languageEnglish
Pages (from-to)145-150
Number of pages6
JournalFEBS Letters
Volume356
Issue number1
DOIs
StatePublished - 14 Dec 1994

Keywords

  • Antiporter
  • Drug resistance
  • Energy coupling
  • H transport
  • Histidine
  • Neurotransmitter transport
  • TEXANS

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