Feline McDonough Sarcoma-like tyrosine kinase (FLT3) is a member of the class III tyrosine kinase receptor family. Ligand binding induces conformational changes in the FLT3 receptor, which facilitates its dimerization and autophosphorylation. Once fully active, FLT3 receptors can associate with growth factor receptor-bound protein 2 (GRB2), which then recruits GRB2-associated-binding protein 2 (GAB2). Consequently, GAB2 is phosphorylated and recruits phosphatidylinositol 3-kinase regulatory subunit alpha (PIK3R1). The p85 alpha subunit of PIK3R1 is known to bind with GAB2. Ultimately, the PI3K/AKT pathway is activated (Zhang et al. 2000, Masson et al. 2009). Experiments confirming this event were performed in mouse cells.