Regulation of the serotonin transporter by interacting proteins

• DOI: 10.1042/bst0290722
• Publication Date: 2005-01-31T12:49:22Z
• Authors: J. Haase; A.-M. Killian; F. Magnani; C. Williams
• Keywords: 0301 basic medicine; 570; Serotonin; Syntaxin 1; Nerve Tissue Proteins; Transfection; Fluorescence; Cell Line; Dose-Response Relationship; Two-Hybrid System Technique; 03 medical and health sciences; Two-Hybrid System Techniques; 616; Animals; Humans; Antigens; Protein Kinase C; Serotonin Plasma Membrane Transport Proteins; Microscopy; 0303 health sciences; Membrane Glycoproteins; Dose-Response Relationship, Drug; Animal; Membrane Transport Proteins; 3. Good health; Surface; Protein Transport; Microscopy, Fluorescence; Nerve Tissue Protein; Antigens, Surface; Membrane Glycoprotein; Drug; Carrier Protein; Carrier Proteins; Serotonin Plasma Membrane Transport Protein; Human; Protein Binding

The serotonin transporter (SERT) plays a critical role in the maintenance of normal neurotransmission by serotonin [5-hydroxytryptamine (5-HT)]. Recent evidence suggests that SERT and other neurotransmitter transporters are tightly regulated. Activation of protein kinase C results in a decrease in SERT-mediated 5-HT uptake, which is due to an internalization of the transporter. However, to date little is known about the mechanism and proteins involved in the down-regulation of the transporter. One candidate SERT-regulatory protein is the SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) protein, syntaxin 1A (Syn1A), which has recently been implicated in the regulation of ion channels as well as the SERT-related γ-aminobutyric acid- and glycine-transporters. Using 5-HT uptake assays, confocal microscopy and glutathione S-transferase (GST) pull-down assays we showed that Syn1A also interacts with SERT and alters the subcellular localization of the transporter, resulting in a reduction of 5-HT transport. In addition, we have used the yeast two-hybrid system to search for novel regulatory proteins that interact with the cytoplasmic N-terminal domain of SERT. By screening rat brain cDNA library we have identified six potential SERT-binding proteins. Here we also present progress towards the elucidation of the biological relevance of these proteins and their potential role for the regulation of the serotonin transporter.