A1 Refereed original research article in a scientific journal
Calpain mobilizes Atg9/Bif-1 vesicles from Golgi stacks upon autophagy induction by thapsigargin
Authors: Marcassa Elena, Raimondi Marzia, Anwar Tahira, Eskelinen Eeva-Liisa, Myers Michael P., Triolo Gianluca, Schneider Claudio, Demarchi Francesca
Publisher: COMPANY OF BIOLOGISTS LTD
Publication year: 2017
Journal: Biology Open
Journal name in source: BIOLOGY OPEN
Journal acronym: BIOL OPEN
Volume: 6
Issue: 5
First page : 551
Last page: 562
Number of pages: 12
ISSN: 2046-6390
eISSN: 2046-6390
DOI: https://doi.org/10.1242/bio.022806
Self-archived copy’s web address: https://research.utu.fi/converis/portal/Publication/30914987
CAPNS1 is essential for stability and function of the ubiquitous calcium-dependent proteases micro- and milli-calpain. Upon inhibition of the endoplasmic reticulum Ca2+ ATPase by 100 nM thapsigargin, both micro- calpain and autophagy are activated in human U2OS osteosarcoma cells in a CAPNS1- dependent manner. As reported for other autophagy triggers, thapsigargin treatment induces Golgi fragmentation and fusion of Atg9/Bif-1-containing vesicles with LC3 bodies in control cells. By contrast, CAPNS1 depletion is coupled with an accumulation of LC3 bodies and Rab5 early endosomes. Moreover, Atg9 and Bif-1 remain in the GM130positive Golgi stacks and Atg9 fails to interact with the endocytic route marker transferrin receptor and with the core autophagic protein Vps34 in CAPNS1-depleted cells. Ectopic expression of a Bif-1 point mutant resistant to calpain processing is coupled to endogenous p62 and LC3-II accumulation. Altogether, these data indicate that calpain allows dynamic flux of Atg9/Bif-1 vesicles from the Golgi toward the budding autophagosome.
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