Further specification and localization of the key molecules involved in SERT regulation, clarification of whether they form stable or transient associations with SERT, and evaluation of how loss of regulation contributes to SERT dysfunction may offer important insights into 5-HT-linked brain disorders such as depression, autism, and obsessive-compulsive disorder (OCD) [12-15]. Here, SLC6A4 is linked to major depressive disorder.