The membrane-bound rat serotonin transporter, SERT1, is an oligomeric protein

The synaptic actions of the neurotransmitter serotonin are terminated by a selective re-uptake system located in the axonal membrane. To gain information about the quaternary structure of this membrane protein, we transiently expressed the recombinant rat serotonin transporter, SERT1, in human embryonic kidney 293 cells. Treatment with sulfhydryl oxidizing agents and the homobifunctional cross-linker dimethyl suberimidate (DMS) generated adducts of 130-180 kDa and 220-270 kDa, respectively. These data indicate an oligomeric structure of SERT1.