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Updated: Oct 26, 2025

Measuring Caspase Activity Using a Fluorometric Assay or Flow Cytometry
Published on: March 24, 2023
Plant type I metacaspases are proteolytically active proteases despite their hydrophobic nature
Katarina Petra van Midden1, Tanja Peric1, Marina Klemenčič1
1Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia.
Abstract:
Plant metacaspases type I (MCA-Is), the closest structural homologs of caspases, are key proteases in stress-induced regulated cell death processes in plants. However, no plant MCA-Is have been characterized in vitro to date. Here, we show that only plant MCA-Is contain a highly hydrophobic loop within the C terminus of their p10 domain. When removed, soluble and proteolytically active plant MCA-Is can be designed and recombinantly produced. We show that the activity of MCA-I depends on calcium ions and that removal of the hydrophobic loop does not affect cleavage and covalent binding to its inhibitor SERPIN. This novel approach will finally allow the development of tools to detect and manipulate the activity of these cysteine proteases in vivo and in planta.
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