SLC6A4 and major depressive disorder: Consequently, future studies might want to explore the biochemical relationship between KLF11 and SLC6A4 function in the context of MDD, especially given that the SLC6A4 promotor region has been shown to contain Sp1 binding sites (Bengel et al. 1997; Heils et al. 1998), which might be targeted by KLF11 (cf. Grunewald et al. 2012).