Mammalian ATG8 proteins maintain autophagosomal membrane integrity through ESCRTs

Ruheena Javed; Ashish Jain; Thabata Duque; Emily Hendrix; Masroor Ahmad Paddar; Sajjad Khan; Aurore Claude-Taupin; Jingyue Jia; Lee Allers; Fulong Wang; Michal Mudd; Graham Timmins; Keith Lidke; Tor Erik Rusten; Prithvi Reddy Akepati; Yi He; Fulvio Reggiori; Eeva-Liisa Eskelinen; Vojo Deretic

doi:10.15252/embj.2022112845

Mammalian ATG8 proteins maintain autophagosomal membrane integrity through ESCRTs

EMBO J. 2023 Jul 17;42(14):e112845. doi: 10.15252/embj.2022112845. Epub 2023 Jun 5.

Authors

Ruheena Javed^{1

2}, Ashish Jain³, Thabata Duque^{1

2}, Emily Hendrix⁴, Masroor Ahmad Paddar^{1

2}, Sajjad Khan⁵, Aurore Claude-Taupin², Jingyue Jia^{1

2}, Lee Allers^{1

2}, Fulong Wang^{1

2}, Michal Mudd^{1

2}, Graham Timmins², Keith Lidke⁵, Tor Erik Rusten³, Prithvi Reddy Akepati⁶, Yi He⁴, Fulvio Reggiori^{7

8}, Eeva-Liisa Eskelinen⁹, Vojo Deretic^{1

2}

Affiliations

¹ Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
² Autophagy, Inflammation and Metabolism Center of Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
³ Faculty of Medicine, University of Oslo, Oslo, Norway.
⁴ Department of Chemistry & Chemical Biology, The University of New Mexico, Albuquerque, NM, USA.
⁵ Department of Physics and Astronomy, The University of New Mexico, Albuquerque, NM, USA.
⁶ Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA.
⁷ Department of Biomedicine, Aarhus University, Aarhus, Denmark.
⁸ Aarhus Institute for Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
⁹ Institute of Biomedicine, University of Turku, Turku, Finland.

PMID: 37272163
PMCID: PMC10350836 (available on 2024-06-05)
DOI: 10.15252/embj.2022112845

Abstract

The canonical autophagy pathway in mammalian cells sequesters diverse cytoplasmic cargo within the double membrane autophagosomes that eventually convert into degradative compartments via fusion with endolysosomal intermediates. Here, we report that autophagosomal membranes show permeability in cells lacking principal ATG8 proteins (mATG8s) and are unable to mature into autolysosomes. Using a combination of methods including a novel in vitro assay to measure membrane sealing, we uncovered a previously unappreciated function of mATG8s to maintain autophagosomal membranes in a sealed state. The mATG8 proteins GABARAP and LC3A bind to key ESCRT-I components contributing, along with other ESCRTs, to the integrity and imperviousness of autophagic membranes. Autophagic organelles in cells lacking mATG8s are permeant, are arrested as amphisomes, and do not progress to functional autolysosomes. Thus, autophagosomal organelles need to be maintained in a sealed state in order to become lytic autolysosomes.

Keywords: ATG8; ESCRT; LC3; amphisome; autophagy.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Animals
Autophagosomes / metabolism
Autophagy*
Autophagy-Related Protein 8 Family / genetics
Autophagy-Related Protein 8 Family / metabolism
Endosomal Sorting Complexes Required for Transport / metabolism
Humans
Mammals
Microtubule-Associated Proteins* / genetics
Microtubule-Associated Proteins* / metabolism

Substances

Autophagy-Related Protein 8 Family
Microtubule-Associated Proteins
Endosomal Sorting Complexes Required for Transport

Abstract

Publication types

MeSH terms

Substances

Grants and funding