title: The WD40 repeat protein WDR-23 functions with the CUL4/DDB1 ubiquitin ligase to regulate nuclear abundance and activity of SKN-1 in Caenorhabditis elegans.
abstract: The transcription factor SKN-1 protects Caenorhabditis elegans from stress and promotes longevity. SKN-1 is regulated by diverse signals that control metabolism, development, and stress responses, but the mechanisms of regulation and signal integration are unknown. We screened the C. elegans genome for regulators of cytoprotective gene expression and identified a new SKN-1 regulatory pathway. SKN-1 protein levels, nuclear accumulation, and activity are repressed by the WD40 repeat protein WDR-23, which interacts with the CUL-4/DDB-1 ubiquitin ligase to presumably target the transcription factor for proteasomal degradation. WDR-23 regulates SKN-1 target genes downstream from p38 mitogen-activated protein kinase, glycogen synthase kinase 3, and insulin-like receptor pathways, suggesting that phosphorylation of SKN-1 may function to modify its interaction with WDR-23 and/or CUL-4/DDB-1. These findings define the mechanism of SKN-1 accumulation in the cell nucleus and provide a new mechanistic framework for understanding how phosphorylation signals are integrated to regulate stress resistance and longevity.
authors.affiliation: Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-2520, USA. keith.p.choe@vanderbilt.edu
authors.forename: Keith P
authors.initials: KP
authors.lastname: Choe
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Przybysz
authors.forename: Kevin
authors.initials: K
authors.lastname: Strange
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D044842:Cullin Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051858:Forkhead Transcription Factors; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D048670:MAP Kinase Kinase 4 / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011972:Receptor, Insulin / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D012097:Repressor Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D029742:Caenorhabditis elegans Proteins; D044842:Cullin Proteins; C517815:DDB-1 protein, C elegans; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D007527:Isoenzymes; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C541018:WDR-23 protein, C elegans; C108831:daf-16 protein, C elegans; C073702:skn-1 protein, C elegans; D005982:Glutathione Transferase; C107483:DAF-2 protein, C elegans; D011972:Receptor, Insulin; D048670:MAP Kinase Kinase 4; C516679:sek-1 protein, C elegans; D046988:Proteasome Endopeptidase Complex