A dualistic conformational response to substrate binding in the human serotonin transporter reveals a high affinity state for serotonin.

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A dualistic conformational response to substrate binding in the human serotonin transporter reveals a high affinity state for serotonin. / Bjerregaard, Henriette; Severinsen, Kasper; Said, Saida; Wiborg, Ove; Sinning, Steffen.

In: Journal of Biological Chemistry, Vol. 290, No. 12, 20.03.2015, p. 7747-55.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

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Bjerregaard, Henriette ; Severinsen, Kasper ; Said, Saida ; Wiborg, Ove ; Sinning, Steffen. / A dualistic conformational response to substrate binding in the human serotonin transporter reveals a high affinity state for serotonin. In: Journal of Biological Chemistry. 2015 ; Vol. 290, No. 12. pp. 7747-55.

Bibtex

@article{eab90ce35e4a44fabbe0bfd5f3b187ba,
title = "A dualistic conformational response to substrate binding in the human serotonin transporter reveals a high affinity state for serotonin.",
abstract = "Serotonergic neurotransmission is modulated by the membrane-embedded serotonin transporter (SERT). SERT mediates the reuptake of serotonin into the presynaptic neurons. Conformational changes in SERT occur upon binding of ions and substrate and are crucial for translocation of serotonin across the membrane. Our understanding of these conformational changes is mainly based on crystal structures of a bacterial homolog in various conformations, derived homology models of eukaryotic neurotransmitter transporters, and substituted cysteine accessibility method of SERT. However, the dynamic changes that occur in the human SERT upon binding of ions, the translocation of substrate, and the role of cholesterol in this interplay are not fully elucidated. Here we show that serotonin induces a dualistic conformational response in SERT. We exploited the substituted cysteine scanning method under conditions that were sensitized to detect a more outward-facing conformation of SERT. We found a novel high affinity outward-facing conformational state of the human SERT induced by serotonin. The ionic requirements for this new conformational response to serotonin mirror the ionic requirements for translocation. Furthermore, we found that membrane cholesterol plays a role in the dualistic conformational response in SERT induced by serotonin. Our results indicate the existence of a subpopulation of SERT responding differently to serotonin binding than hitherto believed and that membrane cholesterol plays a role in this subpopulation of SERT.",
author = "Henriette Bjerregaard and Kasper Severinsen and Saida Said and Ove Wiborg and Steffen Sinning",
year = "2015",
month = "3",
day = "20",
doi = "10.1074/jbc.M114.573477",
language = "English",
volume = "290",
pages = "7747--55",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology, Inc.",
number = "12",

}

RIS

TY - JOUR

T1 - A dualistic conformational response to substrate binding in the human serotonin transporter reveals a high affinity state for serotonin.

AU - Bjerregaard, Henriette

AU - Severinsen, Kasper

AU - Said, Saida

AU - Wiborg, Ove

AU - Sinning, Steffen

PY - 2015/3/20

Y1 - 2015/3/20

N2 - Serotonergic neurotransmission is modulated by the membrane-embedded serotonin transporter (SERT). SERT mediates the reuptake of serotonin into the presynaptic neurons. Conformational changes in SERT occur upon binding of ions and substrate and are crucial for translocation of serotonin across the membrane. Our understanding of these conformational changes is mainly based on crystal structures of a bacterial homolog in various conformations, derived homology models of eukaryotic neurotransmitter transporters, and substituted cysteine accessibility method of SERT. However, the dynamic changes that occur in the human SERT upon binding of ions, the translocation of substrate, and the role of cholesterol in this interplay are not fully elucidated. Here we show that serotonin induces a dualistic conformational response in SERT. We exploited the substituted cysteine scanning method under conditions that were sensitized to detect a more outward-facing conformation of SERT. We found a novel high affinity outward-facing conformational state of the human SERT induced by serotonin. The ionic requirements for this new conformational response to serotonin mirror the ionic requirements for translocation. Furthermore, we found that membrane cholesterol plays a role in the dualistic conformational response in SERT induced by serotonin. Our results indicate the existence of a subpopulation of SERT responding differently to serotonin binding than hitherto believed and that membrane cholesterol plays a role in this subpopulation of SERT.

AB - Serotonergic neurotransmission is modulated by the membrane-embedded serotonin transporter (SERT). SERT mediates the reuptake of serotonin into the presynaptic neurons. Conformational changes in SERT occur upon binding of ions and substrate and are crucial for translocation of serotonin across the membrane. Our understanding of these conformational changes is mainly based on crystal structures of a bacterial homolog in various conformations, derived homology models of eukaryotic neurotransmitter transporters, and substituted cysteine accessibility method of SERT. However, the dynamic changes that occur in the human SERT upon binding of ions, the translocation of substrate, and the role of cholesterol in this interplay are not fully elucidated. Here we show that serotonin induces a dualistic conformational response in SERT. We exploited the substituted cysteine scanning method under conditions that were sensitized to detect a more outward-facing conformation of SERT. We found a novel high affinity outward-facing conformational state of the human SERT induced by serotonin. The ionic requirements for this new conformational response to serotonin mirror the ionic requirements for translocation. Furthermore, we found that membrane cholesterol plays a role in the dualistic conformational response in SERT induced by serotonin. Our results indicate the existence of a subpopulation of SERT responding differently to serotonin binding than hitherto believed and that membrane cholesterol plays a role in this subpopulation of SERT.

UR - http://www.ncbi.nlm.nih.gov/pubmed/25614630

U2 - 10.1074/jbc.M114.573477

DO - 10.1074/jbc.M114.573477

M3 - Journal article

C2 - 25614630

VL - 290

SP - 7747

EP - 7755

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 12

ER -