Background. Protein phosphatase one (PP1) is a ubiquitously expressed, highly conserved protein phosphatase that dephosphorylates target protein serine and threonine residues. PP1 is localized to its site of action by interacting with targeting or regulatory proteins, a majority of which contains a primary docking site referred to as the RVXF/W motif. Results. We demonstrate that a peptide based on the RVXF/W motif can effectively displace PP1 bound proteins from PP1 retained on the phosphatase affinity matrix microcystin-Sepharose. Subsequent co-immunoprecipitation experiments confirmed that each identified binding protein was either a direct PP1 interactor or was in a complex that contains PP1. Our results have linked PP1 to numerous new nuclear functions and proteins, including Ki-67, Rif-1, topoisomerase IIa, several nuclear helicases, NUP153 and the TRRAP complex. Conclusion. This modification of the microcystin-Sepharose technique offers an effective means of purifying novel PP1 regulatory subunits and associated proteins and provides a simple method to uncover a link between PP1 and additional cellular processes.
Moorhead, G. B. G., Trinkle-Mulcahy, L., Nimick, M., De Wever, V., Campbell, D. G., Gourlay, R., Lam, Y. W., & Lamond, A. I. (2008). Displacement affinity chromatography of protein phosphatase one (PP1) complexes. BMC Biochemistry, 9(1). https://doi.org/10.1186/1471-2091-9-28