p62/Sequestosome-1, Autophagy-related Gene 8, and Autophagy in Drosophila Are Regulated by Nuclear Factor Erythroid 2-related Factor 2 (NRF2), Independent of Transcription Factor TFEB.
The selective autophagy receptor p62/sequestosome 1 (SQSTM1) interacts directly with LC3 and is involved in oxidative stress signaling in two ways in mammals. First, p62 is transcriptionally induced upon oxidative stress by the NF-E2-related factor 2 (NRF2) by direct binding to an antioxidant response element in the p62 promoter. Second, p62 accumulation, occurring when autophagy is impaired, leads to increased p62 binding to the NRF2 inhibitor KEAP1, resulting in reduced proteasomal turnover of NRF2. This gives chronic oxidative stress signaling through a feed forward loop. Here, we show that the Drosophila p62/SQSTM1 orthologue, Ref(2)P, interacts directly with DmAtg8a via an LC3-interacting region motif, supporting a role for Ref(2)P in selective autophagy. The ref(2)P promoter also contains a functional antioxidant response element that is directly bound by the NRF2 orthologue, CncC, which can induce ref(2)P expression along with the oxidative stress-associated gene gstD1. However, distinct from the situation in mammals, Ref(2)P does not interact directly with DmKeap1 via a KEAP1-interacting region motif; nor does ectopically expressed Ref(2)P or autophagy deficiency activate the oxidative stress response. Instead, DmAtg8a interacts directly with DmKeap1, and DmKeap1 is removed upon programmed autophagy in Drosophila gut cells. Strikingly, CncC induced increased Atg8a levels and autophagy independent of TFEB/MitF in fat body and larval gut tissues. Thus, these results extend the intimate relationship between oxidative stress-sensing NRF2/CncC transcription factors and autophagy and suggest that NRF2/CncC may regulate autophagic activity in other organisms too.
From the Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway and.
Ashish
A
Jain
the Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Centre for Cancer Biomedicine, University of Oslo, 0379 Oslo, Norway tor.erik.rusten@rr-research.no.
Tor Erik
TE
Rusten
the Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Centre for Cancer Biomedicine, University of Oslo, 0379 Oslo, Norway.
Nadja
N
Katheder
From the Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway and.
Julianne
J
Elvenes
From the Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway and.
Jack-Ansgar
JA
Bruun
From the Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway and.
Eva
E
Sjøttem
From the Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway and.
Trond
T
Lamark
From the Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway and terje.johansen@uit.no.
Terje
T
Johansen
D000595:Amino Acid Sequence; D000818:Animals; D001343:Autophagy / Q000502:physiology*; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D029721:Drosophila Proteins / Q000502:physiology*; D004331:Drosophila melanogaster; D006801:Humans; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000502:physiology*
C527373:Atg8a protein, Drosophila; D017931:DNA Primers; D029721:Drosophila Proteins; D014157:Transcription Factors
autophagy; gene transcription; nuclear factor 2 (erythroid-derived 2-like factor) (NFE2L2) (Nrf2); oxidative stress; p62 (sequestosome 1 (SQSTM1))