Chemical phosphoproteomic approaches reveal substrate specificity of phosphoprotein phosphatases-1 and -2

ABSTRACT: The phosphatases PP1 and PP2A are responsible for the majority of dephosphorylation reactions on phosphoserine (pSer) and –threonine (pThr), and are involved in basically all cellular processes and many related diseases. They are thought to have no appreciable intrinsic substrate specificity, but to gain specificity only in their holoenzyme forms. Through the development of a peptide library approach and application of a complementary phosphoproteomics assay, we uncover that PP1 and PP2A show intrinsic specificity towards pThr over pSer, as well as toward the sequence context surrounding the phospho-site. Our data reveal that PP1 is a key phosphatase of the 14-3-3 protein binding motif. This result enabled us to establish a previously unknown role for PP1 as regulator of the GRB-associated-binding-protein 2 (Gab2)/14-3-3 complex, exemplifying predictive potential of the data. Thus, our work should serve as a rich resource for (de)phosphorylation studies covering multiple cellular processes and phosphoproteins.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Dominic Helm  

LAB HEAD: Mikhail Savitski

PROVIDER: PXD013775 | Pride | 2020-07-14

REPOSITORIES: Pride