KCNJ3 and major depressive disorder: Constitutive knockout of GIRK signaling, including channels expressing the GIRK1 subunit, has been shown to alter anxiety- and depression-like behavior, learning, and memory, as well as motivation for appetitive rewards (Pravetoni and Wickman, 2008; Wydeven et al., 2014; Llamosas et al., 2015; Victoria et al., 2016).