Venditti, M. | Search bioRxiv

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↗

bioRxiv2018

Prolyl Endopeptidase (PREP) is Involved in the Reproductive Functions and Cytoskeletal Organization in Rat Spermatogenesis and in Mammalian Sperm.

Prolyl endopeptidase (PREP) is an enzyme which cleaves several peptide hormones and neuropeptides at the carboxyl side of proline residues, involved in many biological processes, including cell proliferation and differentiation, glucose metabolism, learning, memory and cognitive disorders. Moreover, PREP was identified as binding partner of tubulin, suggesting that this endopeptidase may be involved in microtubule-associate processes, independent of its peptidase activity. Several reports have also suggested PREP participation in both male and female reproduction-associated processes. In this work, we assessed the possible association of PREP with the morphogenesis of rat testis, profiling its localization versus tubulin, during the first wave of spermatogenesis and in the adult gonad (from 7 to 60 dpp). Here we show that, in mitotic phases, PREP shares its localization with tubulin in Sertoli cells, gonocytes and spermatogonia. Later, during meiosis, both proteins are found in spermatocytes, and in the cytoplasm of Sertoli cells protrusions, which surround the germ cells, while, during spermiogenesis, they both localize in the cytoplasm of round and elongating spermatids. Finally, they are expressed in the flagellum of mature gametes, as corroborated by additional immunolocalization analysis on both rat and human sperm. Our data strongly support the hypothesis of a role of PREP in supporting a correct reproductive function and in cytoskeletal organization during Mammalian testis morphogenesis and gamete progression, while also hinting at its possible investigation as a morphological marker of germ cell and sperm physiology.\n\nSummary statementIn this paper we show the co-localization of the enzyme PREP with tubulin during the first wave of rat spermatogenesis and in mature gametes of rat and human.

cell biology↗