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A single serine residue controls the cation dependence of substrate transport by the rat serotonin transporter

Proceedings of the National Academy of SciencesPublished 8 July 1997Open access
Cyrille Sur, Heinrich Betz, Patrick D. Schloss
Citations64

TL;DR

Replacement of serine-545 in the recombinant rat SERT by alanine was found to alter the cation dependence of serotonin uptake, and substrate transport was now driven as efficiently by LiCl as by NaCl without significant changes in serotonin affinity.

Abstract

The serotonin transporter (SERT) is a member of the Na+/Cl--dependent neurotransmitter transporter family and constitutes the target of several clinically important antidepressants. Here, replacement of serine-545 in the recombinant rat SERT by alanine was found to alter the cation dependence of serotonin uptake. Substrate transport was now driven as efficiently by LiCl as by NaCl without significant changes in serotonin affinity. Binding of the antidepressant [3H]imipramine occurred with 1/5th the affinity, whereas [3H]citalopram binding was unchanged. These results indicate that serine-545 is a crucial determinant of both the cation dependence of serotonin transport by SERT and the imipramine binding properties of SERT.

Keywords

NeuroscienceBiochemistry, Genetics and Molecular Biology