Hoeksma, J. | bioRxiv Science

bioRxiv2020

Peptide-based Inhibitors of Protein-Protein Interactions of Src Homology 2 Domain-Containing Phosphatase 2

We developed a new class of inhibitors of protein-protein interactions of the SHP2 phosphatase, which is pivotal in multiple signaling pathways and a central target in the therapy of cancer and rare diseases. Currently available SHP2 inhibitors target the catalytic site or an allosteric pocket but lack specificity or are ineffective on disease-associated SHP2 mutants. Based on the consideration that pathogenic lesions cause signaling hyperactivation due to increased SHP2 association with cognate proteins, we developed peptide-based molecules with low nM affinity for the N-terminal Src homology domain of SHP2, good selectivity, stability to degradation and an affinity for pathogenic variants of SHP2 up to 20 times higher than for the wild-type protein. The best peptide reverted the effects of a pathogenic variant (D61G) in zebrafish embryos. Our results provide a novel route for SHP2-targeted therapies and a tool to investigate the role of protein-protein interactions in the function of SHP2.

biophysics↗

bioRxiv2020

Cercosporamide inhibits bone morphogenetic protein receptor type I kinase activity in zebrafish

Zebrafish models are well established tools for investigating underlying mechanisms of diseases. Here, we identified cercosporamide, a metabolite from the fungus Ascochyta aquiliqiae, as a potent bone morphogenetic protein (BMP) type I receptor kinase inhibitor through a zebrafish embryo phenotypic screen. The developmental defects in zebrafish, including lack of the ventral fin induced by cercosporamide was strikingly similar as the phenotypes caused by renowned small molecule BMP type I receptor kinase inhibitors and inactivating mutations in zebrafish BMP receptors. In mammalian cell-based assays, cercosporamide blocked BMP/SMAD-dependent transcriptional reporter activity and BMP-induced SMAD1/5-phosphorylation. Biochemical assays with a panel of purified recombinant kinases demonstrated that cercosporamide directly inhibited kinase activity of BMP type I receptors (also called activin receptor-like kinases (ALKs)). In mammalian cells, cercosporamide selectively inhibited constitutively active BMP type I receptor-induced SMAD1/5 phosphorylation. Importantly, cercosporamide rescued the developmental defects caused by constitutively active Alk2 in zebrafish embryos. Taken together, we believe cercosporamide may be the first of a new class of molecules with potential to be developed further for clinical use against diseases that are causally linked to overactivation of BMP receptor signaling, including Fibrodysplasia ossificans progressiva and diffuse intrinsic pontine glioma.View Full Text

pharmacology and toxicology↗