Distinct functions of human MVB12A and MVB12B in the ESCRT-I dependent on their posttranslational modifications

Tsunematsu, Takumi; Yamauchi, Emiko; Shibata, Hideki; Maki, Masatoshi; Ohta, Takeshi; Konishi, Hiroaki

doi:10.1016/j.bbrc.2010.07.060

Cited by 21 publications

(26 citation statements)

References 20 publications

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“…Previous studies from our laboratory have provided evidence that UBAP1 selectively associates with ESCRT-I complexes containing VPS37A, supporting a model of functionally distinct ESCRT-I types of defined MVB12 and VPS37 composition (Stefani et al, 2011). In contrast, however, several other studies based on expression of epitope-tagged components have found no such selectivity (Agromayor et al, 2012; Morita et al, 2007a; Tsunematsu et al, 2010), suggesting that the incorporation of VPS37 and MVB12 family members might be stochastic. To further test the selectivity of ESCRT-I function and assembly, we have compared the function of UBAP1 with that of MVB12A and MVB12B during ubiquitin-dependent EGFR sorting to the MVB.…”

Section: Introductionmentioning

confidence: 74%

“…There are three known mammalian proteins that serve as equivalents to Mvb12p based on their ability to integrate into ESCRT-I: MVB12A, MVB12B (Konishi et al, 2006; Morita et al, 2007a; Tsunematsu et al, 2010) and UBAP1 (Agromayor et al, 2012; Stefani et al, 2011). However, there is no sequence conservation between any of these proteins and Mvb12p.…”

Section: Introductionmentioning

confidence: 99%

“…By contrast, modulating the levels of MVB12A or MVB12B profoundly affects the assembly of infective retroviral particles (Morita et al, 2007a), whereas siRNA-mediated depletion of MVB12A or MVB12B only mildly affects the stability of EGFR, as assessed by western blotting (Tsunematsu et al, 2010). Previous studies from our laboratory have provided evidence that UBAP1 selectively associates with ESCRT-I complexes containing VPS37A, supporting a model of functionally distinct ESCRT-I types of defined MVB12 and VPS37 composition (Stefani et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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The molecular basis for selective assembly of the UBAP1-containing, endosome-specific ESCRT-I complex

Wunderley

Brownhill

Stefani

et al. 2013

Journal of Cell Science

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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.

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Section: Introductionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The molecular basis for selective assembly of the UBAP1-containing, endosome-specific ESCRT-I complex

Wunderley

Brownhill

Stefani

et al. 2013

Journal of Cell Science

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“…Humans express a complex array of heterotetrameric ESCRT-I complexes, each of which contains a single copy of the unique human TSG101 subunit and single copies of VPS28 (two variants, A and B), VPS37 (four isoforms, A-D), and MVB12 (at least three isoforms, MVB12A, MVB12B, and UBAP1) (30, 40, 41). Several ESCRT-I subunit isoforms have been shown to function in specific applications (30, 42, 43), but the full range of combinatorial complexity and functional diversity of mammalian ESCRT-I complexes remains to be explored.…”

Section: Early Acting Escrt Factorsmentioning

confidence: 99%

Membrane Fission Reactions of the Mammalian ESCRT Pathway

McCullough

Colf

Sundquist³

2013

Annu. Rev. Biochem.

220

288

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The endosomal sorting complexes required for transport (ESCRT) pathway was initially defined in yeast genetic screens that identified the factors necessary to sort membrane proteins into intraluminal endosomal vesicles. Subsequent studies have revealed that the mammalian ESCRT pathway also functions in a series of other key cellular processes, including formation of extracellular microvesicles, enveloped virus budding, and the abscission stage of cytokinesis. The core ESCRT machinery comprises Bro1 family proteins and ESCRT-I, ESCRT-II, ESCRT-III, and VPS4. Site-specific adaptors recruit these soluble factors to assemble on different cellular membranes, where they carry out membrane fission reactions. ESCRT-III proteins form filaments that draw membranes together from the cytoplasmic face, and mechanistic models have been advanced to explain how ESCRT-III filaments and the VPS4 ATPase can work together to catalyze membrane fission.

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“…Homologs for Mvb12, namely Mvb12A and Mvb12B, have been found. Mvb12A appears to have Ub binding activity as well, but mammalian Mvb12s contribute to ESCRT-dependent virus budding from the plasma membrane and have not been found to be critical for MVB sorting (Morita et al, 2007; Tsunematsu et al, 2010). Recent findings now show that UBAP1, the third “Mvb12-like” ESCRT-I subunit, is the one that endows ESCRT-I with the power to sort Ub-cargo into MVBs {Stefani, 2011 #3;Agromayor, 2012 #4}.…”

mentioning

confidence: 99%