Congratulations to first author Kasia Radziwon and co-authors Laura Campbell, Lauren Mazurkiewicz, Sopo Jalalshvili, Izabelle Eppinger, and Aanika Parikh! We are grateful to the NIH for supporting this work. Public investment in fundamental science fuels innovation and is worth defending.

Leveraging the throughput of our approach, we took a deep dive into the molecular basis of OspF specificity. We identified enzyme residues in the L12 loop that influence OspF’s specificity for pThr vs. pSer and were able to shift this specificity through protein engineering

We also found that the catalytic domain of the pThr lyase OspF (a functionally and mechanistically distinct phosphoeraser from Shigella flexneri) has and intrinsic preference for the pThr-Xaa-pTyr motif found in Erk and p38 MAP kinase activation loops that does not depend on its MAPK docking motif

We applied our approach to define sequence motifs for 8 phosphoerasers spanning diverse species, folds, and enzymatic mechanisms. Example: The Legionella pneumophila phosphatase WipB uses multiple selectivity filters, disfavoring substrates with Pro at +1 and phosphosites flanked by acidic residues

We developed an LC-MS/MS-based in vitro assay for dephosphorylation of human phosphoproteome-derived peptide libraries (PhosPropels). We use statistical comparison of phosphopeptide sequence features in enzyme-treated samples vs. controls for deep specificity profiling of phosphoeraser enzymes.

Phosphorylation is regulated by the activities of writers and erasers. Lots of progress has been made in defining kinase sequence specificity (e.g., www.nature.com/articles/s41...), but there are fewer approaches for studying phosphoeraser specificity

We also found that the catalytic domain of the pThr lyase OspF (a functionally and mechanistically distinct phosphoeraser from Shigella flexneri) has and intrinsic preference for the pThr-Xaa-pTyr motif found in Erk and p38 MAP kinase activation loops that does not depend on its MAPK docking motif

We applied our approach to define sequence motifs for 8 phosphoerasers spanning diverse species, folds, and enzymatic mechanisms. Example: The Legionella pneumophila phosphatase WipB uses multiple selectivity filters, disfavoring substrates with Pro at +1 and phosphosites flanked by acidic residues

We developed an LC-MS/MS-based assay for dephosphorylation of human phosphoproteome-derived peptide libraries (PhosPropels). We use statistical comparison of phosphopeptide sequence features in enzyme-treated samples vs. controls for deep specificity profiling of phosphoerasers.

Phosphorylation is regulated by the activities of writers and erasers. Lots of progress has been made in defining kinase sequence specificity (e.g., www.nature.com/articles/s41...), but there are fewer approaches for studying phosphoeraser specificity

Bravo to Clara Frazier, Debashrito Deb
@thepeptidetailor.bsky.social and coauthors Will Leiter @wleiter1999.bsky.social and Umasankar Mondal!