FAIMS-enabled N-terminomics analysis reveals novel legumain substrates in murine spleen
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ABSTRACT: Legumain is cysteine protease primarily localised to the endo-lysosomal system. Upregulated legumain activity is associated with inflammation, neurodegeneration, and tumorigenesis. Whilst inhibiting legumain in mouse models has demonstrated therapeutic benefit, the proteolytic mechanisms underpinning its various functions are not well known and thus, further characterisation of its physiological substrates is required. Here, we developed FAIMS-enabled N-terminomics for sensitive and streamlined identification of both protein abundance changes and N-termini in complex samples. Comparison of wildtype and legumain-deficient murine spleens identified 6,366 proteins and 2,528 N-termini, of which 235 were enriched in wildtype spleens. These included 119 with asparaginyl cleavages corresponding to 110 proteins, indicating legumain-specific activity. Surprisingly, many of these localised to the nucleus and cytoplasm, hinting at novel extra-lysosomal roles of legumain. We further confirmed the direct processing of selected substrates by legumain in vitro; together, validating FAIMS-enabled N-terminomics for protease substrate detection in an unbiased and systematic manner.
INSTRUMENT(S): Orbitrap Exploris 480
ORGANISM(S): Mus Musculus (mouse)
TISSUE(S): Spleen
SUBMITTER: Nichollas Scott
LAB HEAD: Laura E. Edgington-Mitchell
PROVIDER: PXD043122 | Pride | 2024-07-12
REPOSITORIES: Pride
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