Lysosomal protease deficiency or substrate overload induces an oxidative-stress mediated STAT3-dependent pathway of lysosomal homeostasis

Jonathan Martinez-Fabregas (Lead / Corresponding author), Alan Prescott, Sander van Kasteren, Deena Leslie Pedrioli, William McLean, Anna Moles, Thomas Reinheckel, Valeria Poli, Colin Watts (Lead / Corresponding author)

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Diverse cellular processes depend on the lysosomal protease system but how cells regulate lysosomal proteolytic capacity is only partly understood. We show here that cells can respond to protease/substrate imbalance in this compartment by de novo expression of multiple lysosomal hydrolases. This response, exemplified here either by loss of asparagine endopeptidase (AEP) or other lysosomal cysteine proteases, or by increased endocytic substrate load, is not dependent on the transcription factor EB (TFEB) but rather is triggered by STAT3 activation downstream of lysosomal oxidative stress. Similar lysosomal adaptations are seen in mice and cells expressing a constitutively active form of STAT3. Our results reveal how cells can increase lysosomal protease capacity under ‘fed’ rather than ‘starved’ conditions that activate the TFEB system. In addition, STAT3 activation due to lysosomal stress likely explains the hyperproliferative kidney disease and splenomegaly observed in AEP-deficient mice.
Original languageEnglish
Article number5343
Pages (from-to)1-16
Number of pages16
JournalNature Communications
Issue number1
Publication statusPublished - 17 Dec 2018


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