title: ESCRT proteins restrict constitutive NF-κB signaling by trafficking cytokine receptors.
abstract: Because signaling mediated by the transcription factor nuclear factor κB (NF-κB) is initiated by ligands and receptors that can undergo internalization, we investigated how endocytic trafficking regulated this key physiological pathway. We depleted all of the ESCRT (endosomal sorting complexes required for transport) subunits, which mediate receptor trafficking and degradation, and found that the components Tsg101, Vps28, UBAP1, and CHMP4B were essential to restrict constitutive NF-κB signaling in human embryonic kidney 293 cells. In the absence of exogenous cytokines, depletion of these proteins led to the activation of both canonical and noncanonical NF-κB signaling, as well as the induction of NF-κB-dependent transcriptional responses in cultured human cells, zebrafish embryos, and fat bodies in flies. These effects depended on cytokine receptors, such as the lymphotoxin β receptor (LTβR) and tumor necrosis factor receptor 1 (TNFR1). Upon depletion of ESCRT subunits, both receptors became concentrated on and signaled from endosomes. Endosomal accumulation of LTβR induced its ligand-independent oligomerization and signaling through the adaptors TNFR-associated factor 2 (TRAF2) and TRAF3. These data suggest that ESCRTs constitutively control the distribution of cytokine receptors in their ligand-free state to restrict their signaling, which may represent a general mechanism to prevent spurious activation of NF-κB.
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Mamińska
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Bartosik
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Banach-Orłowska
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Pilecka
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Kamil
authors.initials: K
authors.lastname: Jastrzębski
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Daria
authors.initials: D
authors.lastname: Zdżalik-Bielecka
authors.affiliation: Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland.
authors.forename: Irinka
authors.initials: I
authors.lastname: Castanon
authors.affiliation: Institut de Biologie Valrose, CNRS UMR 7277, INSERM 1091, University of Nice Sophia Antipolis, 06108 Nice, France.
authors.forename: Morgane
authors.initials: M
authors.lastname: Poulain
authors.affiliation: École Polytechnique Fédérale de Lausanne (EPFL), Global Health Institute, 1015 Lausanne, Switzerland.
authors.forename: Claudine
authors.initials: C
authors.lastname: Neyen
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Lidia
authors.initials: L
authors.lastname: Wolińska-Nizioł
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Toruń
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Szymańska
authors.affiliation: Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland.
authors.forename: Agata
authors.initials: A
authors.lastname: Kowalczyk
authors.affiliation: Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Piwocka
authors.affiliation: Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway.
authors.forename: Anne
authors.initials: A
authors.lastname: Simonsen
authors.affiliation: Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, 0379 Oslo, Norway.
authors.forename: Harald
authors.initials: H
authors.lastname: Stenmark
authors.affiliation: Institut de Biologie Valrose, CNRS UMR 7277, INSERM 1091, University of Nice Sophia Antipolis, 06108 Nice, France.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Fürthauer
authors.affiliation: Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland.
authors.forename: Marcos
authors.initials: M
authors.lastname: González-Gaitán
authors.affiliation: International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland. miaczynska@iimcb.gov.pl.
authors.forename: Marta
authors.initials: M
authors.lastname: Miaczynska
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D018121:Receptors, Cytokine / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D015027:Zebrafish / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D016328:NF-kappa B; D018121:Receptors, Cytokine; D029961:Zebrafish Proteins