Figure 4.

Membrane interaction of the individual domains of Akt affected by PIP₃ and PS. SPR sensorgrams representing the membrane binding of Akt RD (a), PH domain (b), and PH domain mutants (c). The GFP-RD or GFP-PH domain of Akt was captured by anti-GFP antibody immobilized on a CM5 chip followed by the injection of liposomes containing PIP₃/PS/PE/PC (x:y:50:[50 − x − y]). Both RD and PH domains showed PS-dependent binding. PH domain mutation (R15A or K20A) significantly impairs the Akt binding to membrane without affecting Akt-PIP₃ interaction (c). Inset, SPR sensorgram showing negligible binding of liposomes to GFP alone.