Control of serotonin transporter phosphorylation by conformational state.
Yuan-Wei Zhang, Benjamin E Turk, Gary Rudnick
Proceedings of the National Academy of Sciences May 17, 2016 DOI: 10.1073/pnas.1603282113 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | HeLa cells expressing SERT and intact rat basophilic leukemia cells |
| Interventions | cocaine ibogaine serotonin |
| Topics | Ibogaine Serotonin |
| Keywords | Phosphorylation Serotonin transporter Conformational regulation |
| Citations | 53 |
| Key findings | Phosphorylation of SERT at threonine 276 is decreased by outward-open conformation stabilizers (Na+, cocaine) and increased by inward-open conformation stabilizers (5-HT, ibogaine), consistent with regulation activated by serotonin transport. |
Abstract
Serotonin transporter (SERT) is responsible for reuptake and recycling of 5-hydroxytryptamine (5-HT; serotonin) after its exocytotic release during neurotransmission. Mutations in human SERT are associated with psychiatric disorders and autism. Some of these mutations affect the regulation of SERT activity by cGMP-dependent phosphorylation. Here we provide direct evidence that this phosphorylation occurs at Thr276, predicted to lie near the cytoplasmic end of transmembrane helix 5 (TM5). Using membranes from HeLa cells expressing SERT and intact rat basophilic leukemia cells, we show that agents such as Na(+) and cocaine that stabilize outward-open conformations of SERT decreased phosphorylation and agents that stabilize inward-open conformations (e.g., 5-HT, ibogaine) increased phosphorylation. The opposing effects of the inhibitors cocaine and ibogaine were each reversed by an excess of the other inhibitor. Inhibition of phosphorylation by Na(+) and stimulation by ibogaine occurred at concentrations that induced outward opening and inward opening, respectively, as measured by the accessibility of cysteine residues in the extracellular and cytoplasmic permeation pathways, respectively. The results are consistent with a mechanism of SERT regulation that is activated by the transport of 5-HT, which increases the level of inward-open SERT and may lead to unwinding of the TM5 helix to allow phosphorylation.
Comparable studies
Other experimental studies on serotonin, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action Healthy human volunteers | 1998 | Experimental study | |
| Amphetamine-type central nervous system stimulants release norepinephrine more potently than they release dopamine and serotonin | 2000 | Experimental study | |
| Methylenedioxyamphetamine (MDA) and methylenedioxymethamphetamine (MDMA) cause selective ablation of serotonergic axon terminals in forebrain: immunocytochemical evidence for neurotoxicity Rat brain | 1988 | Experimental study | |
| The molecular mechanism of "ecstasy" [3,4-methylenedioxy-methamphetamine (MDMA)]: serotonin transporters are targets for MDMA-induced serotonin release. Human platelet plasma membrane vesicles and bovine adrenal chromaffin granule membrane... | 1992 | Laboratory study | |
| 5-HT2AReceptor-Mediated Regulation of Brain-Derived Neurotrophic Factor mRNA in the Hippocampus and the Neocortex Rat brain | 1997 | Experimental study |
Citations in the library
Cited by 5
- Serotonin transporter-ibogaine complexes illuminate mechanisms of inhibition and transport. Nature May 1, 2019
- Structure-based discovery of conformationally selective inhibitors of the serotonin transporter. Cell May 11, 2023
- Conformational dynamics of the human serotonin transporter during substrate and drug binding. Nature Communications April 11, 2019
- Mephedrone induces partial release at human dopamine transporters but full release at human serotonin transporters Neuropharmacology September 11, 2023
- Deciphering Ibogaine’s Matrix Pharmacology: Multiple Transporter Modulation at Serotonin Synapses Journal of the American Chemical Society December 26, 2025
Cites 2
- Ibogaine, a noncompetitive inhibitor of serotonin transport, acts by stabilizing the cytoplasm-facing state of the transporter. Journal of Biological Chemistry October 5, 2007
- The mechanistic basis for noncompetitive ibogaine inhibition of serotonin and dopamine transporters. Journal of Biological Chemistry May 25, 2012