Opy1 and Its3 directly interact. (A) Summary of data from mass spectrometry analysis of proteins associated with Opy1–TAP. T.S.C., total spectral counts. (B) MBP-Trap resin-bound MBP or MBP–Its3 was incubated with GST, GST–Opy1, GST–PH1 or GST–PH2, washed, and the proteins were separated by SDS-PAGE. Representative immunoblot of the in vitro binding assays are shown. The experiment was performed three times with similar results. PD, pull down; IB, immunoblot.