2 research outputs found
Interaction Proteomics Suggests a New Role for the Tfs1 Protein in Yeast
The PEBP (phosphatidylethanolamine-binding protein) family
is a
large group of proteins whose human member, hPEBP1, has been shown
to play multiple functions, influencing intracellular signaling cascades,
cell cycle regulation, neurodegenerative processes, and reproduction.
It also acts, by an unknown mechanism, as a metastasis suppressor
in a number of cancers. A more complete understanding of its biological
role is thus necessary. As the yeast <i>Saccharomyces cerevisiae</i> is a powerful and easy to handle model organism, we focused on Tfs1p,
the yeast ortholog of hPEBP1. In a previous study based on a two-hybrid
approach, we showed that Tfs1p interacts and inhibits Ira2p, a GTPase
Activating Protein (GAP) of the small GTPase Ras. To further characterize
the molecular functions of Tfs1p, we undertook the identification
of protein complexes formed around Tfs1p using a targeted proteomics
approach. Complexed proteins were purified by tandem-affinity, cleaved
with trypsin, and identified by nanoflow liquid chromatography coupled
with tandem mass spectrometry. Overall, 14 new interactors were identified,
including several proteins involved in intermediate metabolism. We
confirmed by co-immunoprecipitation that Tfs1p interacts with Glo3p,
a GAP for Arf GTPases belonging to the Ras superfamily of small GTPases,
indicating that Tfs1p may be involved in the regulation of another
GAP. We similarly confirmed the binding of Tfs1p with the metabolic
enzymes Idp1p and Pro1p. Integration of these results with known functional
partners of Tfs1p shows that two subnetworks meet through the Tfs1p
node, suggesting that it may act as a bridge between cell signaling
and intermediate metabolism in yeast
Design, Synthesis, and Biological Activity of Pyridopyrimidine Scaffolds as Novel PI3K/mTOR Dual Inhibitors
The design, synthesis,
and screening of dual PI3K/mTOR inhibitors
that gave nanomolar enzymatic and cellular activities on both targets
with an acceptable kinase selectivity profile are described. A docking
study was performed to understand the binding mode of the compounds
and to explain the differences in biological activity. In addition,
cellular effects of the best dual inhibitors were determined on six
cancer cell lines and compared to those on a healthy diploid cell
line for cellular cytotoxicity. Two compounds are highly potent on
cancer cells in the submicromolar range without any toxicity on healthy
cells. A more detailed analysis of the cellular effect of these PI3K/mTOR
dual inhibitors demonstrated that they induce G1-phase cell cycle
arrest in breast cancer cells and trigger apoptosis. These compounds
show an interesting kinase profile as dual PI3K/mTOR tool compounds
or as a chemical series for further optimization to progress into
in vivo experiments