Phospho-DAPP1/BAM32 (Tyr139) (D7G4G) Rabbit mAb #13703

The dual adaptor of phosphotyrosine and 3-phosphoinositides (DAPP1/BAM32) is a cytoplasmic adaptor protein that mediates the recruitment and interaction of molecules required for signal transduction downstream of the B cell receptor (BCR) (1). The DAPP1/BAM32 protein contains an amino-terminal SH2 domain and a carboxy-terminal pleckstrin homology (PH) domain that binds to PI3K-derived phosphoinositides (i.e., PIP₃). Upon BCR activation, DAPP1/BAM32 is phosphorylated at specific tyrosine residues and translocated from the cytoplasm to the membrane. Research studies indicate that phosphorylation and translocation of DAPP1/BAM32 is strongly dependent upon PI3K signaling (2,3). The amino-terminal SH2 domain binds to PLCγ2 and other tyrosine-phosphorylated targets. As a result of these interactions, DAPP1/BAM32 can adjust the response to receptor activation by coordinating membrane-localized interactions among proteins of distinct signal transduction pathways (1,4). DAPP1/BAM32 is expressed most abundantly in B lymphocytes; high expression during dendritic cell (DC) maturation and localization to contact sites between DC and allogenic T cells suggest that the DAPP1/BAM32 adaptor may play a role in the activation of T cells through MHC class I-mediated signaling pathways (5).
Research studies show that phosphorylation of DAPP1/BAM32 at Tyr139 is PI3K-dependent, requires an intact PH domain in DAPP1/BAM32, and is likely performed by Src-family kinases following membrane recruitment of DAPP1/BAM32 by phosphoinositides (6). Blocking phosphorylation of DAPP1/BAM32 at Tyr139 inhibits BCR internalization and reduces cellular F-actin levels, suggesting that phosphorylation of DAPP1/BAM32 may play a role in regulating actin-dependent internalization of the activated BCR (7,8).