Immunogen sequence: QLLAYRNGHF FPEQVLNKIE DHSIRELVTQ MIHREPDKRL EAEDYLKQQR GNAFPEIFYT FLQPYMAQFA KETFLSADER ILVIRKDLG. Regulatory subunit of the PI3K complex that mediates formation of phosphatidylinositol 3-phosphate; different complex forms are believe