title: The molecular basis for selective assembly of the UBAP1-containing endosome-specific ESCRT-I complex.
abstract: ESCRT-I is essential for the multivesicular body (MVB) sorting of ubiquitylated cargo such as epidermal growth factor receptor, as well as for several cellular functions, such as cell division and retroviral budding. ESCRT-I has four subunits; TSG101, VPS28, VPS37 and MVB12. There are several members of VPS37 and MVB12 families in mammalian cells, and their differential incorporation into ESCRT-I could provide function-specific variants of the complex. However, it remains unclear whether these different forms of VPS37 and MVB12 combine randomly or generate selective pairings within ESCRT-I, and what the mechanistic basis for such pairing would be. Here, we show that the incorporation of two MVB12 members, UBAP1 and MVB12A, into ESCRT-I is highly selective with respect to their VPS37 partners. We map the region mediating selective assembly of UBAP1-VPS37A to the core ESCRT-I-binding domain of VPS37A. In contrast, selective integration of UBAP1 requires both the minimal ESCRT-I-binding region and a neighbouring predicted helix. The biochemical specificity in ESCRT-I assembly is matched by functional specialisation as siRNA-mediated depletion of UBAP1, but not MVB12A and MVB12B, disrupts ubiquitin-dependent sorting at the MVB.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
authors.forename: Lydia
authors.initials: L
authors.lastname: Wunderley
authors.forename: Kim
authors.initials: K
authors.lastname: Brownhill
authors.forename: Flavia
authors.initials: F
authors.lastname: Stefani
authors.forename: Lydia
authors.initials: L
authors.lastname: Tabernero
authors.forename: Philip
authors.initials: P
authors.lastname: Woodman
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D056827:Endosomal Sorting Complexes Required for Transport / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011992:Endosomes / Q000235:genetics*; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D046912:Multiprotein Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport / Q000235:genetics; D034741:RNA, Small Interfering; D014157:Transcription Factors / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism; D000099177:Tsg101 Protein
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D066246:ErbB Receptors; D046912:Multiprotein Complexes; D034741:RNA, Small Interfering; D014157:Transcription Factors; D025801:Ubiquitin; D033921:Vesicular Transport Proteins; D000099177:Tsg101 Protein; C552120:MVB12B protein, human; C469867:UBAP1 protein, human; C496437:VPS37A protein, human; C512478:EGFR protein, human
keywords: EGFR; ESCRT-I; Endosome; MVB12; TSG101; UBAP1; VPS37