Systematic Discovery of Short Linear Motifs Decodes Calcineurin Phosphatase Signaling.

Short linear motifs (SLiMs) drive dynamic protein-protein interactions essential for signaling, but sequence degeneracy and low binding affinities make them difficult to identify. We harnessed unbiased systematic approaches for SLiM discovery to elucidate the regulatory network of calcineurin (CN)/PP2B, the Ca-activated phosphatase that recognizes LxVP and PxIxIT motifs. In vitro proteome-wide detection of CN-binding peptides, in vivo SLiM-dependent proximity labeling, and in silico modeling of motif determinants uncovered unanticipated CN interactors, including NOTCH1, which we establish as a CN substrate.

The human DEPhOsphorylation Database DEPOD: 2019 update.

The human Dephosphorylation Database (DEPOD) is a manually curated resource that harbors human phosphatases, their protein and non-protein substrates, dephosphorylation sites and the associated signaling pathways. We report here an update to DEPOD by integrating and/or linking to annotations from 69 other open access databases including disease associations, phosphorylating kinases, protein interactions, and also genome browsers. We also provide tools to visualize protein interactions, protein structures, phosphorylation networks, evolutionary conservation of proteins, dephosphorylation sites, and short linear motifs within various proteins.

Quantitative mapping of protein-peptide affinity landscapes using spectrally encoded beads.

Transient, regulated binding of globular protein domains to Short Linear Motifs (SLiMs) in disordered regions of other proteins drives cellular signaling. Mapping the energy landscapes of these interactions is essential for deciphering and perturbing signaling networks but is challenging due to their weak affinities. We present a powerful technology (MRBLE-pep) that simultaneously quantifies protein binding to a library of peptides directly synthesized on beads containing unique spectral codes.

Mechanism of autophosphorylation of mycobacterial PknB explored by molecular dynamics simulations.

Mycobacterial Ser/Thr kinase, PknB, is essential for the growth of the pathogen. Unphosphorylated PknB is catalytically inactive, and its activation requires autophosphorylation of Thr residues on the activation loop. Autophosphorylation can in principle take place via two distinct mechanisms.

Deciphering kinase-substrate relationships by analysis of domain-specific phosphorylation network.

Motivation: In silico prediction of site-specific kinase-substrate relationships (ssKSRs) is crucial for deciphering phosphorylation networks by linking kinomes to phosphoproteomes. However, currently available predictors for ssKSRs give rise to a large number of false-positive results because they use only a short sequence stretch around phosphosite as determinants of kinase specificity and do not consider the biological context of kinase-substrate recognition.

Results: Based on the analysis of domain-specific kinase-substrate relationships, we have constructed a domain-level phosphorylation network that implicitly incorporates various contextual factors.