The serotonin transporter (SERT) is a target of various therapeutic agents used in the treatment of neurological and neurodegenerative disorders. The present invention provides novel forms of SERT that lacks high affinity recognition of specific serotonin reuptake inhibitors (SSRIs). The present invention therefore provides a novel target for use in screening and model development that can aid both the discovery of new medications and the discovery of novel pathways impacted in parallel with SERT blockade. Such novel targets can help identify new SSRI's with unique modifications and lead to discovery of pathways that secondarily support the therapeutic activity of these agents.