Promyelocytic leukemia (PML) protein forms the basis of PML nuclear bodies (PML NBs), which control many important processes. We have screened an shRNA library targeting ubiquitin pathway proteins for effects on PML NBs, and identified RNF8 and RNF168 DNA-damage response proteins as negative regulators of PML NBs. Additional studies confirmed that depletion of either RNF8 or RNF168 increased the levels of PML NBs and proteins, whereas overexpression induced loss of PML NBs. RNF168 partially localized to PML NBs through its UMI/MIU1 ubiquitin-interacting region and associated with NBs formed by any PML isoform. The association of RNF168 with PML NBs resulted in increased ubiquitylation and SUMO2 modification of PML. In addition, RNF168 was found to associate with proteins modified by SUMO2 and/or SUMO3 in a manner dependent on its ubiquitin-binding sequences, suggesting that hybrid SUMO-ubiquitin chains can be bound. In vitro assays confirmed that RNF168, preferentially, binds hybrid SUMO2-K63 ubiquitin chains compared with K63-ubiquitin chains or individual SUMO2. Our study identified previously unrecognized roles for RNF8 and RNF168 in the regulation of PML, and a so far unknown preference of RNF168 for hybrid SUMO-ubiquitin chains.
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http://dx.doi.org/10.1242/jcs.176446 | DOI Listing |
FEBS Lett
December 2024
Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Canada.
Promyelocytic leukemia (PML) protein forms the scaffold for PML nuclear bodies (PML NB) that reorganize into Lipid-Associated PML Structures (LAPS) under fatty acid stress. We determined how the fatty acid oleate alters the interactome of PMLI or PMLII by expressing fusions with the ascorbate peroxidase APEX2 in U2OS cells. The resultant interactome included ESCRT and COPII transport protein nodes.
View Article and Find Full Text PDFCell Death Dis
December 2024
National Resource Center for Mutant Mice, MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, 210061, China.
Fish Physiol Biochem
February 2025
Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato, Tokyo, 108-8477, Japan.
Cell lines derived from fish tissues are resistant to premature senescence under typical culture conditions. Previously, we demonstrated that fish genomes do not have a p16/Arf locus and that the absence of this locus underlies the lack of senescence in cultured fish cells. However, other factors may also contribute to this resistance.
View Article and Find Full Text PDFChem Sci
December 2024
Schulich Faculty of Chemistry, Technion Israel Institute of Technology Haifa 3200008 Israel
The Small Ubiquitin-like Modifier (SUMO) is a crucial post-translational modifier of proteins, playing a key role in various cellular functions. All SUMOs are synthesized as precursor proteins that must be proteolytically processed. However, the maturation process of cleaving the extending C-terminal tail, preceding SUMOylation of substrates, remains poorly understood, especially within cellular environments.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Université Claude Bernard Lyon 1, Centre national de la recherche scientifique (CNRS) UMR 5261, Institut national de la santé et de la recherche médicale (Inserm) U1315, Laboratoire d'Excellence (LabEx) DEV2CAN, Institut NeuroMyoGène-Pathophysiology and Genetics of Neuron and Muscle (INMG-PGNM), team "Chromatin dynamics, Nuclear Domains, Virus", Lyon 69008, France.
Herpes simplex virus 1 (HSV-1) latently infected neurons display diverse patterns in the distribution of the viral genomes within the nucleus. A key pattern involves quiescent HSV-1 genomes sequestered in promyelocytic leukemia nuclear bodies (PML NBs) forming viral DNA-containing PML-NBs (vDCP NBs). Using a cellular model that replicates vDCP NB formation, we previously demonstrated that these viral genomes are chromatinized with the H3.
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