Although kinase mutations have been identified in various human diseases, much less is known about protein phosphatases. Here, we show that all apoptosis-stimulating proteins of p53 (ASPP) family members can bind protein phosphatase 1 (PP1) via two distinct interacting motifs. ASPP2 interacts with PP1 through an RVXF PP1 binding motif, whereas the inhibitory member of the ASPP family (iASPP) interacts with PP1 via a noncanonical motif (RNYF) that is located within its Src homology 3 domain (SH3). Phe-815 is crucial in mediating iASPP/PP1 interaction, and iASPP(F815A) fails to inhibit the transcriptional and apoptotic function of p53. This study identifies iASPP as a new binding partner of PP1, interacting through a noncanonical PP1 binding motif.
J Biol Chem
43039 - 43044
Amino Acid Motifs, Apoptosis Regulatory Proteins, Cell Line, Tumor, Flow Cytometry, Humans, Immunoprecipitation, Intracellular Signaling Peptides and Proteins, Protein Binding, Protein Phosphatase 1, Repressor Proteins