In this article we report on a fast and simple approach for proteomic profiling of protease specificities (fast profiling of protease specificity (FPPS)), which can be applied to complex protein mixtures. FPPS is based on trideutero-acetylation of novel N-termini generated by the action of proteases and subsequent peptide fractionation on Stage Tips containing ion-exchange and reverse phase chromatographic resins. FPPS can be performed in 2 days and does not require extensive fractionation steps. Using this approach, we have determined the specificity profiles of the cysteine cathepsins K, L and S. We further validated our method by comparing the results with the specificity profiles obtained by the N-terminal combined fractional diagonal chromatography method.
COBISS.SI-ID: 28342823
Here we show using a mass spectrometry-based approach that cathepsins L and S act as sheddases and cleave extracellular domains of CAM adhesion proteins and transmembrane receptors from the surface of cancer cells. In cathepsin S-deficient mouse pancreatic cancers, processing of these cathepsin substrates is highly reduced, pointing to an essential role of cathepsins in extracellular shedding. In addition to influencing cell migration and invasion, shedding of surface proteins by extracellular cathepsins impacts intracellular signaling as demonstrated for regulation of Ras GTPase activity, thereby providing a putative mechanistic link between extracellular cathepsin activity and cancer progression.
COBISS.SI-ID: 28696103