DAPP1 (BAM32) is recruited to the plasma membrane by the binding of its PH domain to phosphoinositol 3,4,5-trisphosphate (PIP3) (Dowler et al. 1999, Marshall et al. 2000, Ferguson et al. 2000). DAPP1 also binds phosphatidylinositol 3,4-bisphosphate (Dowler et al. 1999, Ferguson et al. 2000) and therefore remains bound at the plasma membrane after PIP3 has been dephosphorylated by phosphatases. At the plasma membrane DAPP1 is phosphorylated by a Src family kinase, likely LYN in B cells (Dowler et al. 2000).