title: A dual role for K63-linked ubiquitin chains in multivesicular body biogenesis and cargo sorting.
abstract: In yeast, the sorting of transmembrane proteins into the multivesicular body (MVB) internal vesicles requires their ubiquitylation by the ubiquitin ligase Rsp5. This allows their recognition by the ubiquitin-binding domains (UBDs) of several endosomal sorting complex required for transport (ESCRT) subunits. K63-linked ubiquitin (K63Ub) chains decorate several MVB cargoes, and accordingly we show that they localize prominently to the class E compartment, which accumulates ubiquitylated cargoes in cells lacking ESCRT components. Conversely, yeast cells unable to generate K63Ub chains displayed MVB sorting defects. These properties are conserved among eukaryotes, as the mammalian melanosomal MVB cargo MART-1 is modified by K63Ub chains and partly missorted when the genesis of these chains is inhibited. We show that all yeast UBD-containing ESCRT proteins undergo ubiquitylation and deubiquitylation, some being modified through the opposing activities of Rsp5 and the ubiquitin isopeptidase Ubp2, which are known to assemble and disassemble preferentially K63Ub chains, respectively. A failure to generate K63Ub chains in yeast leads to an MVB ultrastructure alteration. Our work thus unravels a double function of K63Ub chains in cargo sorting and MVB biogenesis.
authors.affiliation: Institut Jacques Monod, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7592, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Zoi
authors.initials: Z
authors.lastname: Erpapazoglou
authors.forename: Manel
authors.initials: M
authors.lastname: Dhaoui
authors.forename: Marina
authors.initials: M
authors.lastname: Pantazopoulou
authors.forename: Francesca
authors.initials: F
authors.lastname: Giordano
authors.forename: Muriel
authors.initials: M
authors.lastname: Mari
authors.forename: Sébastien
authors.initials: S
authors.lastname: Léon
authors.forename: Graça
authors.initials: G
authors.lastname: Raposo
authors.forename: Fulvio
authors.initials: F
authors.lastname: Reggiori
authors.forename: Rosine
authors.initials: R
authors.lastname: Haguenauer-Tsapis
mesh_terms: D002451:Cell Compartmentation; D056827:Endosomal Sorting Complexes Required for Transport / Q000737:chemistry* / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D058965:MART-1 Antigen / Q000378:metabolism; D057146:Multivesicular Bodies / Q000378:metabolism* / Q000648:ultrastructure; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D058965:MART-1 Antigen; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; D008239:Lysine