May act as a B-cell-associated adapter that regulates B-cell antigen receptor (BCR)-signaling downstream of PI3K. Interacts with PtdIns(3,4,5)P3 and PLCG2. In vitro, interacts with PtdIns(3,4)P2. Membrane-associated after cell stimulation leading to its translocation. Highly expressed in placenta and lung, followed by brain, heart, kidney, liver, pancreas and skeletal muscle. Expressed by B-lymphocytes, but not T-lymphocytes or nonhematopoietic cells. Upon B-cell activation. Phosphorylated on tyrosine residues.