Activity profiling of vacuolar processing enzymes reveals a role for VPE during oomycete infection |
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Authors: | Johana C Misas‐Villamil Gerrit Toenges Izabella Kolodziejek Amir M Sadaghiani Farnusch Kaschani Thomas Colby Matthew Bogyo Renier AL van der Hoorn |
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Institution: | 1. The Plant Chemetics Laboratory, Max Planck Institute for Plant Breeding Research, , 50829 Cologne, Germany;2. Department of Pathology, Stanford School of Medicine, , Stanford, CA, 94305 USA;3. Proteomics Service Center, Max Planck Institute for Plant Breeding Research, , 50829 Cologne, Germany |
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Abstract: | Vacuolar processing enzymes (VPEs) are important cysteine proteases that are implicated in the maturation of seed storage proteins, and programmed cell death during plant–microbe interactions and development. Here, we introduce a specific, cell‐permeable, activity‐based probe for VPEs. This probe is highly specific for all four Arabidopsis VPEs, and labeling is activity‐dependent, as illustrated by sensitivity for inhibitors, pH and reducing agents. We show that the probe can be used for in vivo imaging and displays multiple active isoforms of VPEs in various tissues and in both monocot and dicot plant species. Thus, VPE activity profiling is a robust, simple and powerful tool for plant research for a wide range of applications. Using VPE activity profiling, we discovered that VPE activity is increased during infection with the oomycete pathogen Hyaloperonospora arabidopsidis (Hpa). The enhanced VPE activity is host‐derived and EDS1‐independent. Sporulation of Hpa is reduced on vpe mutant plants, demonstrating a role for VPE during compatible interactions that is presumably independent of programmed cell death. Our data indicate that, as an obligate biotroph, Hpa takes advantage of increased VPE activity in the host, e.g. to mediate protein turnover and nutrient release. |
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Keywords: | protease activity profiling legumain
VPE
aza‐epoxide caspase  1 activity‐based protein profiling technical advance |
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