We report here on a rapid in vivo high-throughput method, using yeast and the redox dye TTC to screen chemical libraries and identify inhibitors of respiratory function. We applied Sorafenib B-Raf that screening process, followed by a series of tests, to a diverse library of 4,640 molecules and identified a weak inhibitor of complex III without toxic effect on the cell. Interestingly, that drug (D12) is fully active against the mutant enzyme harboring the G143A mutation that confers a high level of resistance toward most of the fungicides targeting complex III but is not active against bovine complex III. Using a collection of yeast strains harboring mutations in the inhibitor binding sites (Q(o) and Q(i) sites), we showed that D12 targeted the Q(o) site and that its inhibitory activity was weakened by the mutation L275F.

A phenylalanine is naturally present at position 275 in mammalian complex III, which could explain the differential sensitivity toward D12. The molecule is not structurally related to commercial inhibitors of complex III and could potentially be used as a lead compound for the development of antimicrobial agents.
PTPRJ is a receptor-type protein tyrosine phosphatase whose expression is strongly reduced in the majority of investigated cancer cell lines and tumor specimens. PTPRJ negatively interferes with mitogenic signals originating from several oncogenic receptor tyrosine kinases, including HGFR, PDGFR, RET, and VEGFR-2. Here we report the isolation and characterization of peptides from a random peptide phage display library that bind and activate PTPRJ.

These agonist peptides, which are able to both circularize and form dimers in acqueous solution, were assayed for their biochemical and biological activity on both human cancer cells and primary endothelial cells (HeLa and HUVEC, respectively). Our results demonstrate that GSK-3 binding of PTPRJ-interacting peptides to cell cultures dramatically reduces the extent of both MAPK phosphorylation and total phosphotyrosine levels; conversely, they induce a significant increase of the cell cycle inhibitor p27K(iPl). Moreover, PTPRJ agonist peptides both reduce proliferation and trigger apoptosis of treated cells. Our data indicate that peptide agonists of PTPRJ Rucaparib supplier positively modulate the PTPRJ activity and may lead to novel targeted anticancer therapies.
The microtubule associated protein tau (MAPT/tau) aberrantly accumulates in 15 neurodegenerative diseases, termed tauopathies. One way to treat tauopathies may be to accelerate tau clearance, but the molecular mechanisms governing tau stability are not yet clear. We recently identified chemical probes that markedly accelerate the clearance of tau in cellular and animal models.