This Src/Fyn-SIRPα-Shp2 pathway seems to be mobilized to reduce depression risk since mutant mice lacking most of the tyrosine-phosphorylated cytoplasmic region of SIRPα or lacking the SIRPα ligand CD47 manifested the increased immobility time relative to wild-type (WT) mice. Here, FYN is linked to major depressive disorder.