Ribbon representation of the PI3K α. Ribbon representation of the PI3Kα helical domain (blue) and kinase domain (magenta) extracted from the p110α/p85α complex (PDB Code: 2RD0; Berman et al. (2000) ; Huang et al. (2007) ). Displayed in CPK representations are sites of major oncogenic mutations: Pro539, Glu542, Glu545 and Gln546 in the helical domain (blue); Arg1023, Thr1025, His1047 and Gly1049 in the kinase domain (pink). The ATP binding site in the kinase domain is highlighted with a surface.