USP15 stabilizes the transcription factor Nrf1 in the nucleus, promoting the proteasome gene expression

Fukagai, Kousuke; Waku, Tsuyoshi; Chowdhury, A. M. Masudul Azad; Kubo, Kaori; Matsumoto, Mariko; Kato, Hiroki; Natsume, Tohru; Tsuruta, Fuminori; Chiba, Tomoki; Taniguchi, Hiroaki; Kobayashi, Akira

doi:10.1016/j.bbrc.2016.07.045

Cited by 23 publications

(19 citation statements)

References 24 publications

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“…By sharp contrast, further pulse-chase experiments revealed that the stability of Nrf1-derived protein-A to -D was significantly enhanced upon the proteasomal inhibition by MG132 (at 10 mol/L) ( Figure 5B, lanes 7-11), so that their half-lives were substantially prolonged to 1.54 h (=92 min), 1.90 h (=114 min), over 4 h (=240 min) and more than 4 h (=240 min), respectively, after co-treatment of si-Hrd1 cells with CHX ( Figure 5C, right panel). Together with the previous reports of Hrd1 acting as a retrotranslocon candidate involved in ERAD [64][65][66][67], these results indicate that dynamic repositioning of Nrf1 may be partially retarded by knockdown of Hrd1, so that its longer protein-A/B isoforms are modestly accumulated. However, it cannot be ruled out that a small fraction of Nrf1 are permitted by a hitherto unidentified mechanism to be presented for the proteolytic processing of the CNC-bZIP protein by MG132-sensitive proteases, besides proteasomes.…”

Section: Knockdown Of Hrd1 Causes An Accumulation Of the Longer Isofosupporting

confidence: 83%

Molecular mechanisms controlling the multistage post-translational processing of endogenous Nrf1α/TCF11 proteins to yield distinct proteoforms within the coupled positive and negative feedback circuits

Xiang

Wang

et al. 2018

Preprint

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In an attempt to terminate the chaotic state of the literature on Nrf1/TCF11 with various confused molecular masses, we herein establish a generally acceptable criterion required for identification of its endogenous full-length proteins and derivative isoforms expressed differentially in distinct experimental cell lines. Further work has been focused on the molecular mechanisms that dictate the successive multistate post-translational modifications (i.e. glycosylation by OST, deglycosylation by NGLY, and ubiquitination by Hrd1) of this CNC-bZIP protein and its proteolytic processing to yield multiple isoforms. Several lines of experimental evidence have demonstrated that the nascent Nrf1/TCF11 polypeptide (non-glycosylated) is transiently translocated into the endoplasmic reticulum (ER), in which it becomes an inactive glycoprotein-A, and also folded in a proper topology within and around membranes. Thereafter, dynamic repositioning of the ER-resident domains in Nrf1 glycoprotein is driven by p97-fueled retrotranslocation into extra-ER compartments. Therein, glycoprotein of Nrf1 is allowed for digestion into a deglycoprotein-B and then its progressive proteolytic processing by cytosolic DDI-1/2 and proteasomes to yield distinct proteoforms (i.e. protein-C/D). The processing is accompanied by removal of a major N-terminal ~12.5-kDa polypeptide from Nrf1. Interestingly, our present study has further unraveled that coupled positive and negative feedback circuits exist between Nrf1 and its cognate target genes, including those encoding its regulators p97, Hrd1, DDI-1 and proteasomes. These key players are differentially or even oppositely involved in diverse cellular signalling responses to distinct extents of ER-derived proteotoxic and oxidative stresses induced by different concentrations of proteasomal inhibitors.

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Section: Knockdown Of Hrd1 Causes An Accumulation Of the Longer Isofosupporting

confidence: 83%

Molecular mechanisms controlling the multistage post-translational processing of endogenous Nrf1α/TCF11 proteins to yield distinct proteoforms within the coupled positive and negative feedback circuits

Xiang

Wang

et al. 2018

Preprint

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“…As shown in the left panel of Fig. 2C, NRF1 is resistant to KEAP1-mediated degradation, consistent with previous studies (45,46). In contrast, overexpressed NRF2 is degraded by overexpressed KEAP1 (Fig.…”

Section: Neh2l Has Conserved Dlg and Etge Motifs But Is Refractory Tosupporting

confidence: 91%

“…Because NRF1 and NRF2 are both responsive to oxidative stress and the main sensor of oxidative stress for the transcription of ARE-driven genes is KEAP1, a persisting question has been why NRF1 is not regulated by KEAP1. The Neh2-like (Neh2L) domain of NRF1 p140, p120, p110, p95, and p85 isoforms contains the DLG and ETGE motifs, and although previous studies have detected NRF1-KEAP1 interactions, NRF1 has not been found to be degraded by KEAP1 (45,46). ER localization of NRF1 may prevent NRF1-KEAP1 interactions; however, because NRF1 conserves the Neh2L, suggesting that it could be a KEAP1 substrate, we investigated whether cytosolic NRF1 can be degraded by KEAP1.…”

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confidence: 97%

Kelch-like ECH-associated protein 1 (KEAP1) differentially regulates nuclear factor erythroid-2–related factors 1 and 2 (NRF1 and NRF2)

Wang¹,

Vega²,

Schmidlin

et al. 2018

Journal of Biological Chemistry

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Nuclear factor erythroid-2-related factor 1 (NRF1) and NRF2 are essential for maintaining redox homeostasis and coordinating cellular stress responses. They are highly homologous transcription factors that regulate the expression of genes bearing antioxidant-response elements (AREs). Genetic ablation of or results in vastly different phenotypic outcomes, implying that they play different roles and may be differentially regulated. Kelch-like ECH-associated protein 1 (KEAP1) is the main negative regulator of NRF2 and mediates ubiquitylation and degradation of NRF2 through its NRF2-ECH homology-like domain 2 (Neh2). Here, we report that KEAP1 binds to the Neh2-like (Neh2L) domain of NRF1 and stabilizes it. Consistently, NRF1 is more stable in than in isogenic cell lines, whereas NRF2 is dramatically stabilized in cells. Replacing NRF1's Neh2L domain with NRF2's Neh2 domain renders NRF1 sensitive to KEAP1-mediated degradation, indicating that the amino acids between the DLG and ETGE motifs, not just the motifs themselves, are essential for KEAP1-mediated degradation. Systematic site-directed mutagenesis identified the core amino acid residues required for KEAP1-mediated degradation and further indicated that the DLG and ETGE motifs with correct spacing are insufficient as a KEAP1 degron. Our results offer critical insights into our understanding of the differential regulation of NRF1 and NRF2 by KEAP1 and their different physiological roles.

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“…It is speculated that Nrf1 and Nrf2 up-regulate proteasome genes through recognition of upstream ARE sequences. Ubiquitin-specific protease 15 (USP15) has been suggested to activate Nrf1 function in the nucleus by stabilizing Nrf1 through its deubiquitination[165]. Furthermore, activation of mTORC1 signaling stimulates Nrf1 activity, leading to increased levels of proteasomes[166].…”

Section: Regulation Of Proteasome Expressionmentioning

confidence: 99%

Proteasome Structure and Assembly

Budenholzer

Cheng

et al. 2017

Journal of Molecular Biology

315

280

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The eukaryotic 26S proteasome is a large multi-subunit complex that degrades the majority of proteins in the cell under normal conditions. The 26S proteasome can be divided into two subcomplexes: the 19S regulatory particle (RP) and the 20S core particle (CP). Most substrates are first covalently modified by ubiquitin, which then directs them to the proteasome. The function of the RP is to recognize, unfold, deubiquitylate and translocate substrates into the CP, which contains the proteolytic sites of the proteasome. Given the abundance and subunit complexity of the proteasome, the assembly of this ~2.5 MDa complex must be carefully orchestrated to ensure its correct formation. In recent years, significant advances have been made in the understanding of proteasome assembly, structure and function. Technical advances in cryo-electron microscopy have resulted in a series of atomic cryo-EM structures of both human and yeast 26S proteasomes. These structures have illuminated new intricacies and dynamics of the proteasome. In this review, we focus on the mechanisms of proteasome assembly, particularly in light of recent structural information.

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USP15 stabilizes the transcription factor Nrf1 in the nucleus, promoting the proteasome gene expression

Cited by 23 publications

References 24 publications

Molecular mechanisms controlling the multistage post-translational processing of endogenous Nrf1α/TCF11 proteins to yield distinct proteoforms within the coupled positive and negative feedback circuits

Molecular mechanisms controlling the multistage post-translational processing of endogenous Nrf1α/TCF11 proteins to yield distinct proteoforms within the coupled positive and negative feedback circuits

Kelch-like ECH-associated protein 1 (KEAP1) differentially regulates nuclear factor erythroid-2–related factors 1 and 2 (NRF1 and NRF2)

Proteasome Structure and Assembly

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