Docking Motif-Guided Mapping of the Interactome of Protein Phosphatase-1

The ubiquitous protein Ser/Thr phosphatase-1 (PP1) interacts with dozens of regulatory proteins that are structurally unrelated. However, most of them share a short, degenerate RVxF-type docking motif. Using a broad in silico screening based on a stringent definition of the RVxF motif, in combination with a multistep biochemical validation procedure, we have identified 78 novel mammalian PP1 interactors. A global analysis of the validated RVxF-based PP1 interactome not only provided insights into the conserved features of the RVxF motif but also led to the discovery of additional common 13131 binding elements, described as the SILK and MyPhoNE motifs. In addition to the doubling of the known mammalian PP1 interactome, our data contribute to the design of PP1 interaction networks. Notably, an interaction network linking PP1 interactors; discloses a pleiotropic role of PP1 in cell polarity.