DNA damage modulates nucleolar interaction of the Werner protein with the AAA ATPase p97/VCP.
We report a novel nucleolar interaction between the AAA ATPase p97/VCP and the Werner protein (WRNp), a member of the RecQ helicase family. p97/VCP mediates several important cellular functions in eucaryotic cells, including membrane fusion of the endoplasmic reticulum and Golgi and ubiquitin-dependent protein degradation. Mutations in the WRN gene cause Werner syndrome, a genetic disorder characterized by premature onset of aging symptoms, a higher incidence of cancer, and a high susceptibility to DNA damage caused by topoisomerase inhibitors. We observed that both WRNp and valosin-containing protein (VCP) were present in the nucleoplasm and in nucleolar foci in mammalian cells and that WRNp and p97/VCP physically interacted in the nucleoli. Importantly, the nucleolar WRNp/VCP complex was dissociated by treatment with camptothecin, an inhibitor of topoisomerase I, whereas other WRNp-associated protein complexes, such as WRNp/Ku 80, were not dissociated by this drug. Because WRN syndrome cells are sensitive to topoisomerase inhibitors, these observations suggest that the VCP/WRNp interaction plays an important role in WRN biology. We propose a novel role for VCP in the DNA damage response pathway through modulation of WRNp availability.
Partridge
Juneth Joaquin
JJ
Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Lopreiato
Joseph Onofrio
JO
Latterich
Martin
M
Indig
Fred Eliezer
FE
D000251:Adenosine Triphosphatases; D000818:Animals; D034961:Antigens, Nuclear / Q000378:metabolism; D002166:Camptothecin / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002466:Cell Nucleolus / Q000378:metabolism*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004249:DNA Damage / Q000502:physiology*; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005090:Exodeoxyribonucleases; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D000072200:Ku Autoantigen; D008561:Membrane Fusion / Q000502:physiology; D051379:Mice; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases; D000074405:Valosin Containing Protein; D014898:Werner Syndrome / Q000235:genetics / Q000378:metabolism*; D000071657:Werner Syndrome Helicase
D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005090:Exodeoxyribonucleases; D000251:Adenosine Triphosphatases; D004265:DNA Helicases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; C000606510:Xrcc6 protein, mouse; C000614178:VCP protein, human; D000074405:Valosin Containing Protein; C000614179:Vcp protein, mouse; D000072200:Ku Autoantigen; D004264:DNA Topoisomerases, Type I; D002166:Camptothecin