title: Keap1/Cullin3 Modulates p62/SQSTM1 Activity via UBA Domain Ubiquitination.
abstract: p62/SQSTM1 (p62) is a scaffolding protein that facilitates the formation and degradation of ubiquitinated aggregates via its self-interaction and ubiquitin binding domains. The regulation of this process is unclear but may relate to the post-translational modification of p62. In the present study, we find that Keap1/Cullin3 ubiquitinates p62 at lysine 420 within its UBA domain. Substitution of lysine 420 with an arginine diminishes p62 sequestration and degradation activity similar what is seen when the UBA domain is deleted. Overexpression of Keap1/Cullin3 in p62-WT-expressing cells increases ubiquitinated inclusion formation and p62's association with LC3 and rescues proteotoxicity. This effect is not seen in cells expressing a mutant p62 that fails to interact with Keap1. Interestingly, p62 disease mutants have diminished or absent UBA domain ubiquitination. These data suggest that the ubiquitination of p62's UBA domain at lysine 420 may regulate p62's function and be disrupted in p62-associated disease.
authors.affiliation: Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: YouJin
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Medical Center and Los Angeles Biomedical Research Institute, Torrance, CA 90502, USA.
authors.forename: Tsui-Fen
authors.initials: TF
authors.lastname: Chou
authors.affiliation: Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Sara K
authors.initials: SK
authors.lastname: Pittman
authors.affiliation: Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Keith
authors.affiliation: Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Babak
authors.initials: B
authors.lastname: Razani
authors.affiliation: Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA. Electronic address: weihlc@wustl.edu.
authors.forename: Conrad C
authors.initials: CC
authors.lastname: Weihl
mesh_terms: D019943:Amino Acid Substitution; D001343:Autophagy / Q000502:physiology; D002478:Cells, Cultured; D044842:Cullin Proteins / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D000072019:Kelch-Like ECH-Associated Protein 1 / Q000378:metabolism*; D008239:Lysine / Q000235:genetics; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011485:Protein Binding; D011743:Pyrimidines / Q000378:metabolism; D000071456:Sequestosome-1 Protein / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases; D054875:Ubiquitination / Q000502:physiology*
chemical_list: D044842:Cullin Proteins; D003517:Cyclopentanes; D047908:Intracellular Signaling Peptides and Proteins; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D011743:Pyrimidines; C099718:SQSTM1 protein, human; D000071456:Sequestosome-1 Protein; D025801:Ubiquitin; C412480:UBAC1 protein, human; D044767:Ubiquitin-Protein Ligases; D008239:Lysine; C539933:pevonedistat
keywords: SQSTM1/p62; aggregaphagy; autophagy; neurodegeneration; ubiquitin