(D) Endogenous Gad8-HA was affinity purified from starved cells, in order to activate its kinase activity (left and middle panels), and mixed with recombinant, purified GST-Taf12, GST-Taf12-5A, or GST-Fkh2 proteins (right panels) in a kinase assay buffer. Each assay was then analyzed by IB and probed with an anti-phospho-AKT substrate antibody. 