Concentrative ER export of the serotonin transporter relies exclusively on an interaction with Sec24C

Abstract

Background The transporters for serotonin (SERT), dopamine (DAT) and noradrenaline (NET) form the monoamine neurotransmitter transporter family. They are primarily responsible for the termination of neurotransmission via rapid reuptake of neurotransmitters from the synaptic cleft. We have previously shown that the C-terminus of SERT plays a key role in trafficking and folding of the transporter. Mutations in this region of the protein (specifically at sites PG and RI) cause intracellular retention of SERT, hence abolishing substrate uptake and reducing inhibitor binding. In the current study, we explored isoform-specific interaction of COPII component Sec24 proteins with monoamine transporters, to study the mechanistic nature of their ER export.