Figure 3. PP1Ba and PP1Bb interact with Mypt1 in vitro.

(A) Schematic of GST fusion proteins used for co-sedimentation. The N-terminal 300 amino-acids of zebrafish Mypt1 are fused to GST with either a WT KVKF or mutated KMKF PP1 binding motif. (B and C) Increasing concentrations of purified GST fusion proteins (indicated protein added in micrograms) were incubated with glutathione sepharose and used to sediment GFP-tagged PP1Ba and PP1Bb from HEK293T cell lystates. GST alone was used as a negative control. The co-sedimented proteins were analyzed by SDS-PAGE and immunoblotted using an anti-GFP (B) or anti-GST antibody (C). A vertical bar indicates the presence of a lane removed from the western blot in editing.