High-Throughput Kinetic Characterization of Irreversible Covalent Inhibitors of KRAS by Intact Protein MS and Targeted MRM.

With recent advances and success in several drugs designed to treat acute and chronic diseases, targeted covalent inhibitors show a resurgence in drug discovery. As covalent inhibition is time-dependent, the preferred quantitative potency metric of irreversible inhibitors is the second-order rate constant /, rather than IC. Here, we present the development of a mass spectrometry-based platform for rapid kinetic analysis of irreversible covalent inhibitors.

Cereblon Promotes the Ubiquitination and Proteasomal Degradation of Interleukin Enhancer-Binding Factor 2.

Interleukin enhancer-binding factor 2 (ILF2) forms a heterodimer with interleukin enhancer-binding factor 3 (ILF3) via double-stranded RNA-binding motif and zinc finger associated domain and thus regulates gene expression and cancer cell growth. However, how ILF2 is degraded in cells remains elusive. In this work, using stable isotope labeling by amino acids in cell culture (SILAC) quantitative proteomics, we find that ILF2 is downregulated in cells expressing cereblon (CRBN).

[Inhibition of PI3K/AKT signaling pathway promotes the nuclear translocation of B7-H4].

Objective: To investigate the regulatory effect of phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) signaling pathway on the subcellular distribution of negative co-stimulatory molecule B7-H4.

Methods: The HEK293 cells transfected stably with B7-H4, named B7-H4/HEK293, were treated with the PI3K/AKT specific inhibitor LY294002 and/or the nuclear export inhibitor leptomycin B (LMB). The subcellular localization of B7-H4 in B7-H4/HEK293 was observed by immunofluorescence and confocal laser scanning microscopy (CLSM), and the expression levels of B7-H4 in membrane, cytoplasm and nuclear were detected by Western blotting.