Martina Bielefeld-Sevigny

Université du Québec à Montréal, Montréal, Quebec, Canada

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Publications (4)6.39 Total impact

  • Martina Bielefeld-Sevigny
    Assay and Drug Development Technologies 03/2009; 7(1):90-2. DOI:10.1089/adt.2009.9996 · 2.08 Impact Factor
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    ABSTRACT: Small ubiquitin-like proteins (SUMO) are recently discovered post-translational modifiers that regulate protein functions and intracellular trafficking. In this study, we are describing two chemoluminescence-based assays, one for SUMOylation and another one for SUMO-mediated protein-protein interactions. These assays can be used to characterize the activity and kinetics of the enzymes that catalyze SUMOylation, and in high-throughput screening for inhibitors of SUMOylation and SUMO-dependent protein-protein interactions. These novel assays represent the most sensitive assays for ubiquitin-like systems published to date. Similar strategies can be used to develop assays for other ubiquitin-like modification systems.
    Analytical Biochemistry 05/2008; 375(2):364-6. DOI:10.1016/j.ab.2007.11.024 · 2.31 Impact Factor
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    ABSTRACT: Protein kinases are directly implicated in many human diseases; therefore, kinase inhibitors show great promises as new therapeutic drugs. In an effort to facilitate the screening and the characterization of kinase inhibitors, a novel application of the AlphaScreen technology was developed to monitor JNK activity from (1) purified kinase preparations and (2) endogenous kinase from cell lysates preactivated with different cytokines. The authors confirmed that both adenosine triphosphate (ATP) competitive as well as peptide-based JNK inhibitors were able to block the activity of both recombinant and HepG2 endogenous JNK activity. Using the same luminescence technique adapted for binding studies, the authors characterized peptide inhibitor mechanisms by measuring the binding affinity of the inhibitors for JNK. Because of the versatility of the technology, this cell-based JNK kinase assay could be adapted to other kinases and would represent a powerful tool to evaluate endogenous kinase activity and test a large number of potential inhibitors in a more physiologically relevant environment.
    Journal of Biomolecular Screening 01/2007; 11(8):1015-26. DOI:10.1177/1087057106294697 · 2.01 Impact Factor
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    ABSTRACT: 40 Peptide 40 Peptide (A (Aβ β β β β β β β40) in 40) in Cell Cell Culture Culture Supernatants Supernatants 7 Abstract Abstract Although various methods exist for detection and quantification of low analyte concentrations, ELISA is still the most widely adopted method. This non-homogeneous technology offers great selectivity, sensitivity and assay versatility, however has certain limitations like a limited throughput due to wash steps, a generally narrow dynamic range and the incapacity to use low affinity antibodies. The new AlphaLISA™ platform does not face those limitations. As it does not require any wash steps, assay development is simple and fast, and hands-on time as well as total assay time are largely reduced. The assays are easy to miniaturize and automate enabling an efficient High Throughput Screening set-up. Like standard ELISA assays, AlphaLISA assays can be designed as either sandwich or competition immunoassays. Our team successfully developed a multitude of different assays for detection and quantification of analytes from cell culture supernatants, cell lysates and serum/plasma samples. The range of analytes tested includes small molecules (like Substance P) up to large complexes (IgG's to full size phage particles). Excellent performance could be demonstrated with dynamic ranges up to 4.5 log of analyte concentration in the sample, sensitivities below 1 pg/mL with high accuracy and precision. A broad selection of examples, including several biomarkers, will be presented. The results do not only prove that AlphaLISA can be used universally instead of ELISA, but also that AlphaLISA is an enabling technology for applications where measuring low affinity interactions between two or more binding partners is required. This, together with its ease of use, makes AlphaLISA THE alternative generic technology platform replacing ELISA.