A Pull-down assay of lysates from untransfected P1.HTR cells with unphosphorylated (YENM) and tyrosine-phosphorylated (pYENM) IDO1 peptides, analyzed by immunoblotting with anti-p85, -p110α, -p110β, -p110γ, and -p110δ antibodies. Whole cell lysates (WCL) were used as control of lysate amount. 