The Drosophila ZER1 homolog interacts with ref(2)P to regulate autophagy and Keap1-cnc/NFE2L2/Nrf2-mediated oxidative stress

The ubiquitin-proteasome system (UPS) and macroautophagy/autophagy are two major pathways for maintaining cellular protein homeostasis. Increasing evidence has highlighted the complex interactions and crosstalk between these pathways; however, the specific molecules and mechanisms mediating the interplay between the UPS and autophagy are still not fully elucidated. In this study, we discovered that knocking down the Drosophila Cul2 (Cullin 2)-RING ubiquitin ligase complex adaptor CG12084/DmZer1 impedes autophagy and autophagic flux. DmZer1 interacts with the Drosophila SQSTM1/p62 homolog ref(2)P, promoting its association with ubiquitinated proteins and degradation. ref(2)P is a crucial player in regulating autophagy and the Keap1-cnc/NFE2L2 pathway-mediated antioxidant response. Knockdown of DmZer1 leads to the formation of ref(2)P bodies, which sequester Keap1 and promote cnc/NFE2L2-mediated antioxidant responses under oxidative stress conditions. These findings reveal the pivotal role of DmZer1 in regulating autophagy and the ref(2)P-Keap1-cnc/NFE2L2-mediated oxidative stress response.Abbreviations: ARM: armadillo-like domain; ATG: autophagy related; BTZ: bortezomib; CL1-GFP: GFP fused with a CL1 degron; cnc: cap-n-collar; co-IP: co-immunoprecipitation; CRL2: Cullin 2-RING E3 ubiquitin ligase complex; CQ: chloroquine; CUL2/Cul2: cullin 2; EloB: Elongin B; EloC: Elongin C; esg: escargot; ISCs: intestinal stem cells; KEAP1: kelch like ECH associated protein 1; LIR: LC3-interacting region; LLPS: liquid-liquid phase separation; LRR: leucine-rich repeat; NFE2L2/Nrf2: NFE2 like bZIP transcription factor 2; p-H3: phospho-histone H3; PQ: paraquat; ref(2)P: refractory to sigma P; SQSTM1/p62: sequestosome 1; UBA: ubiquitin-associated; UPS: ubiquitin-proteasome system; VHL: von Hippel-Lindau tumor suppressor; ZER1: zyg-11 related cell cycle regulator.