Journal: Cell reports

Article Title: Molecular basis of vesicular monoamine transport and neurological drug interactions

doi: 10.1016/j.celrep.2025.116490

Figure Lengend Snippet: (A) VMAT-mediated monoamine storage, release, and drug interactions in neurons and neuroendocrine cells. VMAT1 and 2 accumulate various monoamines (MA, green spheres) in secretory vesicles via proton (2H + ) antiport. This process is facilitated by the rocker-switch transition of VMATs, alternating between lumenal-facing and cytoplasmic-facing conformations. Amphetamine (AMPH, red sphere) promotes vesicular monoamine release via VMATs. Reserpine (RSP) and tetrabenazine (TBZ) inhibit VMAT2 in the cytoplasmic-facing and periplasmic-facing conformations, respectively. The N-terminal domain (NTD) and C-terminal domain (CTD) of VMAT2 are colored in blue and red, respectively. (B) VMAT2-del maintains the wild-type (WT) VMAT2 function. Vesicular uptake of [ 3 H]-serotonin (top) and [ 3 H]-dopamine (bottom) was measured in HEK293T cells after plasma membrane permeabilization. VMAT2-del shows activities similar to WT, and both activities are inhibited by bafilomycin A (BFA), which collapses the proton gradient, and by VMAT2-specific inhibitors, reserpine and tetrabenazine. (C–H) Cryo-EM density maps (left) and structures (right) of VMAT2 in unbound state (C) (map contoured at 0.03 in ChimeraX), VMAT2 with serotonin (D) (map contour 0.015), VMAT2 with histamine (E) (map contour 0.005), VMAT2 with amphetamine (F) (map contour 0.002), VMAT2 with reserpine (G) (map contour 0.03), and VMAT2 with tetrabenazine (H) (map contour 0.03). See also - and .

Article Snippet: For reserpine and TBZ-bound samples, the purified CcO-VMAT2-del complex were incubated with 100 μM reserpine (Sigma) or 100 μM TBZ (MCE) for 2 h on ice and further purified by size exclusion chromatography on a Superdex 200 Increase 10/300 column (GE Healthcare) in 150 mM NaCl, 0.01% (w/v) LMNG, 0.0033% (w/v) GDN, and 20 mM Tris-HCl, pH 8.0.

Techniques: Clinical Proteomics, Membrane, Cryo-EM Sample Prep

Journal: Cell reports

Article Title: Molecular basis of vesicular monoamine transport and neurological drug interactions

doi: 10.1016/j.celrep.2025.116490

Figure Lengend Snippet: (A) Tetrabenazine binding interactions. The density map for tetrabenazine (TBZ) is shown (contoured at 0.03 in ChimeraX), and the surrounding residues are colored by the NTD and CTD. (B) Chemical structure of tetrabenazine and scheme of binding interactions. (C) Comparison of tetrabenazine and serotonin binding. Tetrabenazine shares interacting residues with serotonin but extends beyond the serotonin binding site, engaging with several additional residues, especially in the CTD. (D) Overall structure of VMAT2 with tetrabenazine in the lumenal-facing, fully occluded conformation. (E) Comparison of the fully occluded conformation (blue: NTD, red: CTD) with the histamine-bound, lumenal-open conformation (gray colors), and the ligand-free, partially occluded conformation (cyan: NTD, orange: CTD). The structures are superimposed by the NTD to show local differences. Residues forming the NTD-CTD interface at the lumen side of the full-occluded conformation are shown. Glycines (yellow spheres) and prolines contributing to the structural flexibility of VMAT2 are indicated. (F) [ 3 H]-dihydrotetrabenazine ([ 3 H]-DTBZ) binding of wild-type VMAT2 and mutants. The binding experiments are carried out at 10 nM [ 3 H]-DTBZ, and the retained radioactivity is normalized to wild type. Errors are SEM from three repeats. (G) [ 3 H]-DTBZ binding curves of VMAT2 and VMAT1. Distinct residues of VMAT2 and VMAT1 at the tetrabenazine binding site are replaced with the corresponding ones. VMAT1-LVY: triple substitutions of F38L, L240V, and F441Y in human VMAT1, which correspond to L37, V232, and Y433 in human VMAT2. The counts of [ 3 H]-DTBZ specifically bound to each construct are normalized to the maximum number of [ 3 H]-DTBZ counts ( B max ) bound to wild-type VMAT2. Errors are SEM from three repeats. See also .

Article Snippet: For reserpine and TBZ-bound samples, the purified CcO-VMAT2-del complex were incubated with 100 μM reserpine (Sigma) or 100 μM TBZ (MCE) for 2 h on ice and further purified by size exclusion chromatography on a Superdex 200 Increase 10/300 column (GE Healthcare) in 150 mM NaCl, 0.01% (w/v) LMNG, 0.0033% (w/v) GDN, and 20 mM Tris-HCl, pH 8.0.

Techniques: Binding Assay, Comparison, Radioactivity, Construct