PPP3R1 and major depressive disorder: - Decreased expression in the mouse model of depression. - Mediates chronic stress-induced depression-like phenotype by altering hippocampal neurogenesis and neuroplasticity via controlling epigenetic and transcription regulators, such as Mll3 and Runx1; and cell signaling regulators, like Socs3, Ppp3r1, Gpr125, and Nrp1.