scholarly journals The circuitry of cargo flux in the ESCRT pathway

2009 ◽  
Vol 185 (2) ◽  
pp. 185-187 ◽  
Author(s):  
James H. Hurley ◽  
Xuefeng Ren
Keyword(s):  
Membrane Proteins ◽  
Binding Site ◽  
Degradation Pathway ◽  
Multivesicular Bodies ◽  
Lysosomal Degradation ◽  
Endosomal Sorting ◽  
Cell Biol ◽  
Ubiquitin Binding ◽  
In Series

The endosomal sorting complex required for transport (ESCRT) complexes sort ubiquitinated membrane proteins into multivesicular bodies, which is a key step in the lysosomal degradation pathway. Shields et al. (Shields, S.B., A.J. Oestreich, S. Winistorfer, D. Nguyen, J.A. Payne, D.J. Katzmann, and R. Piper. 2009. J. Cell Biol. 185:213–224) identify a new ubiquitin-binding site in ESCRT-I and provide evidence that the upstream ESCRT-I and -II complexes sort cargo in parallel rather than in series.

scholarly journals Revisiting caveolin trafficking: the end of the caveosome

2010 ◽  
Vol 191 (3) ◽  
pp. 439-441 ◽  
Author(s):  
Robert G. Parton ◽  
Mark T. Howes
Keyword(s):  
Membrane Proteins ◽  
Multivesicular Bodies ◽  
Endosomal Sorting ◽  
Cell Biol ◽  
New Findings

In this issue, a study by Hayer et al. (2010. J. Cell Biol. doi: 10.1083/jcb.201003086) provides insights into the trafficking of caveolins, the major membrane proteins of caveolae. As well as providing evidence for ubiquitin-mediated endosomal sorting and degradation of caveolin in multivesicular bodies (MVBs), the new findings question the existence of a unique organelle proposed nine years ago, the caveosome.

scholarly journals ESCRT ubiquitin-binding domains function cooperatively during MVB cargo sorting

2009 ◽  
Vol 185 (2) ◽  
pp. 213-224 ◽  
Author(s):  
S. Brookhart Shields ◽  
Andrea J. Oestreich ◽  
Stanley Winistorfer ◽  
Doris Nguyen ◽  
Johanna A. Payne ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Structural Information ◽  
Multivesicular Bodies ◽  
Endosomal Sorting ◽  
Binding Domains ◽  
Ubiquitin Binding ◽  
Cargo Sorting

Ubiquitin (Ub) sorting receptors facilitate the targeting of ubiquitinated membrane proteins into multivesicular bodies (MVBs). Ub-binding domains (UBDs) have been described in several endosomal sorting complexes required for transport (ESCRT). Using available structural information, we have investigated the role of the multiple UBDs within ESCRTs during MVB cargo selection. We found a novel UBD within ESCRT-I and show that it contributes to MVB sorting in concert with the known UBDs within the ESCRT complexes. These experiments reveal an unexpected level of coordination among the ESCRT UBDs, suggesting that they collectively recognize a diverse set of cargo rather than act sequentially at discrete steps.

scholarly journals Ubiquitin binding by the CUE domain promotes endosomal localization of the Rab5 GEF Vps9

2015 ◽  
Vol 26 (7) ◽  
pp. 1345-1356 ◽  
Author(s):  
Tess Shideler ◽  
Daniel P. Nickerson ◽  
Alexey J. Merz ◽  
Greg Odorizzi
Keyword(s):  
Membrane Trafficking ◽  
Guanine Nucleotide Exchange Factors ◽  
Multivesicular Bodies ◽  
Nucleotide Exchange ◽  
Binding Motifs ◽  
Endosomal Sorting ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Ubiquitin Binding ◽  
Cue Domain

Vps9 and Muk1 are guanine nucleotide exchange factors (GEFs) in Saccharomyces cerevisiae that regulate membrane trafficking in the endolysosomal pathway by activating Rab5 GTPases. We show that Vps9 is the primary Rab5 GEF required for biogenesis of late endosomal multivesicular bodies (MVBs). However, only Vps9 (but not Muk1) is required for the formation of aberrant class E compartments that arise upon dysfunction of endosomal sorting complexes required for transport (ESCRTs). ESCRT dysfunction causes ubiquitinated transmembrane proteins to accumulate at endosomes, and we demonstrate that endosomal recruitment of Vps9 is promoted by its ubiquitin-binding CUE domain. Muk1 lacks ubiquitin-binding motifs, but its fusion to the Vps9 CUE domain allows Muk1 to rescue endosome morphology, cargo trafficking, and cellular stress-tolerance phenotypes that result from loss of Vps9 function. These results indicate that ubiquitin binding by the CUE domain promotes Vps9 function in endolysosomal membrane trafficking via promotion of localization.

scholarly journals Protein crowding mediates membrane remodeling in upstream ESCRT-induced formation of intraluminal vesicles

2020 ◽  
Vol 117 (46) ◽  
pp. 28614-28624
Author(s):  
Susanne Liese ◽  
Eva Maria Wenzel ◽  
Ingrid Kjos ◽  
Rossana Rojas Molina ◽  
Sebastian W. Schultz ◽  
...  
Keyword(s):  
Degradation Pathway ◽  
Bending Rigidity ◽  
Lysosomal Degradation ◽  
Endosomal Sorting ◽  
Electron Microscopy Analysis ◽  
Steep Decline ◽  
Microscopy Analysis ◽  
Protein Crowding ◽  
Membrane Shape

As part of the lysosomal degradation pathway, the endosomal sorting complexes required for transport (ESCRT-0 to -III/VPS4) sequester receptors at the endosome and simultaneously deform the membrane to generate intraluminal vesicles (ILVs). Whereas ESCRT-III/VPS4 have an established function in ILV formation, the role of upstream ESCRTs (0 to II) in membrane shape remodeling is not understood. Combining experimental measurements and electron microscopy analysis of ESCRT-III–depleted cells with a mathematical model, we show that upstream ESCRT-induced alteration of the Gaussian bending rigidity and their crowding in concert with the transmembrane cargo on the membrane induce membrane deformation and facilitate ILV formation: Upstream ESCRT-driven budding does not require ATP consumption as only a small energy barrier needs to be overcome. Our model predicts that ESCRTs do not become part of the ILV, but localize with a high density at the membrane neck, where the steep decline in the Gaussian curvature likely triggers ESCRT-III/VPS4 assembly to enable neck constriction and scission.

scholarly journals Bro1 stimulates Vps4 to promote intralumenal vesicle formation during multivesicular body biogenesis

2021 ◽  
Vol 220 (8) ◽  
Author(s):  
Chun-Che Tseng ◽  
Shirley Dean ◽  
Brian A. Davies ◽  
Ishara F. Azmi ◽  
Natalya Pashkova ◽  
...  
Keyword(s):  
Multivesicular Body ◽  
Vesicle Formation ◽  
Multivesicular Bodies ◽  
Membrane Remodeling ◽  
Endosomal Sorting ◽  
Aaa Atpase ◽  
Ubiquitin Binding ◽  
Stimulation Of ◽  
Cargo Sorting

Endosomal sorting complexes required for transport (ESCRT-0, -I, -II, -III) execute cargo sorting and intralumenal vesicle (ILV) formation during conversion of endosomes to multivesicular bodies (MVBs). The AAA-ATPase Vps4 regulates the ESCRT-III polymer to facilitate membrane remodeling and ILV scission during MVB biogenesis. Here, we show that the conserved V domain of ESCRT-associated protein Bro1 (the yeast homologue of mammalian proteins ALIX and HD-PTP) directly stimulates Vps4. This activity is required for MVB cargo sorting. Furthermore, the Bro1 V domain alone supports Vps4/ESCRT–driven ILV formation in vivo without efficient MVB cargo sorting. These results reveal a novel activity of the V domains of Bro1 homologues in licensing ESCRT-III–dependent ILV formation and suggest a role in coordinating cargo sorting with membrane remodeling during MVB sorting. Moreover, ubiquitin binding enhances V domain stimulation of Vps4 to promote ILV formation via the Bro1–Vps4–ESCRT-III axis, uncovering a novel role for ubiquitin during MVB biogenesis in addition to facilitating cargo recognition.

scholarly journals Arabidopsis SH3P2 is an ubiquitin-binding protein that functions together with ESCRT-I and the deubiquitylating enzyme AMSH3

2017 ◽  
Vol 114 (34) ◽  
pp. E7197-E7204 ◽  
Author(s):  
Marie-Kristin Nagel ◽  
Kamila Kalinowska ◽  
Karin Vogel ◽  
Gregory D. Reynolds ◽  
Zhixiang Wu ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Stress Responses ◽  
Binding Protein ◽  
In Planta ◽  
Biotic And Abiotic Stress ◽  
Plasma Membrane Proteins ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Ubiquitin Binding

Clathrin-mediated endocytosis of plasma membrane proteins is an essential regulatory process that controls plasma membrane protein abundance and is therefore important for many signaling pathways, such as hormone signaling and biotic and abiotic stress responses. On endosomal sorting, plasma membrane proteins maybe recycled or targeted for vacuolar degradation, which is dependent on ubiquitin modification of the cargos and is driven by the endosomal sorting complexes required for transport (ESCRTs). Components of the ESCRT machinery are highly conserved among eukaryotes, but homologs of ESCRT-0 that are responsible for recognition and concentration of ubiquitylated proteins are absent in plants. Recently several ubiquitin-binding proteins have been identified that serve in place of ESCRT-0; however, their function in ubiquitin recognition and endosomal trafficking is not well understood yet. In this study, we identified Src homology-3 (SH3) domain-containing protein 2 (SH3P2) as a ubiquitin- and ESCRT-I–binding protein that functions in intracellular trafficking. SH3P2 colocalized with clathrin light chain-labeled punctate structures and interacted with clathrin heavy chain in planta, indicating a role for SH3P2 in clathrin-mediated endocytosis. Furthermore, SH3P2 cofractionates with clathrin-coated vesicles (CCVs), suggesting that it associates with CCVs in planta. Mutants of SH3P2 and VPS23 genetically interact, suggesting that they could function in the same pathway. Based on these results, we suggest a role of SH3P2 as an ubiquitin-binding protein that binds and transfers ubiquitylated proteins to the ESCRT machinery.

scholarly journals Ear1p and Ssh4p Are New Adaptors of the Ubiquitin Ligase Rsp5p for Cargo Ubiquitylation and Sorting at Multivesicular Bodies

2008 ◽  
Vol 19 (6) ◽  
pp. 2379-2388 ◽  
Author(s):  
Sébastien Léon ◽  
Zoi Erpapazoglou ◽  
Rosine Haguenauer-Tsapis
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Ubiquitin Ligase ◽  
Multivesicular Bodies ◽  
Endosomal Sorting ◽  
Frame Fusion ◽  
Vacuolar Targeting

The ubiquitylation of membrane proteins destined for the vacuole/lysosome is essential for their recognition by the endosomal sorting machinery and their internalization into vesicles of multivesicular bodies (MVBs). In yeast, this process requires Rsp5p, an essential ubiquitin ligase of the Nedd4 family. We describe here two redundant proteins, Ear1p and Ssh4p, required for the vacuolar targeting of several cargoes originating from the Golgi or the plasma membrane. Ear1p is an endosomal protein that interacts with Rsp5p through its PPxY motifs, and it is required for the ubiquitylation of selected cargoes before their MVB sorting. In-frame fusion of cargo to ubiquitin overcomes the need for Ear1p/Ssh4p, confirming a role for these proteins in cargo ubiquitylation. Interestingly, Ear1p is itself ubiquitylated by Rsp5p and targeted to the vacuole. Finally, Ear1p overexpression leads to Rsp5p accumulation at endosomes, interfering with some of its functions in trafficking. Therefore, Ear1p/Ssh4p recruit Rsp5p and assist it in its function at MVBs by directing the ubiquitylation of specific cargoes.

scholarly journals Coordinated binding of Vps4 to ESCRT-III drives membrane neck constriction during MVB vesicle formation

2014 ◽  
Vol 205 (1) ◽  
pp. 33-49 ◽  
Author(s):  
Manuel Alonso Y Adell ◽  
Georg F. Vogel ◽  
Mehrshad Pakdel ◽  
Martin Müller ◽  
Herbert Lindner ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Adenosine Triphosphatase ◽  
Electron Tomography ◽  
Vesicle Formation ◽  
Multivesicular Bodies ◽  
Membrane Remodeling ◽  
Yeast Genetics ◽  
Endosomal Sorting ◽  
Distinct Membrane

Five endosomal sorting complexes required for transport (ESCRTs) mediate the degradation of ubiquitinated membrane proteins via multivesicular bodies (MVBs) in lysosomes. ESCRT-0, -I, and –II interact with cargo on endosomes. ESCRT-II also initiates the assembly of a ringlike ESCRT-III filament consisting of Vps20, Snf7, Vps24, and Vps2. The AAA–adenosine triphosphatase Vps4 disassembles and recycles the ESCRT-III complex, thereby terminating the ESCRT pathway. A mechanistic role for Vps4 in intraluminal vesicle (ILV) formation has been unclear. By combining yeast genetics, biochemistry, and electron tomography, we find that ESCRT-III assembly on endosomes is required to induce or stabilize the necks of growing MVB ILVs. Yet, ESCRT-III alone is not sufficient to complete ILV biogenesis. Rather, binding of Vps4 to ESCRT-III, coordinated by interactions with Vps2 and Snf7, is coupled to membrane neck constriction during ILV formation. Thus, Vps4 not only recycles ESCRT-III subunits but also cooperates with ESCRT-III to drive distinct membrane-remodeling steps, which lead to efficient membrane scission at the end of ILV biogenesis in vivo.

scholarly journals Interactions of ubiquitin and CHMP5 with the V domain of HD-PTP reveals role for regulation of Vps4 ATPase

2021 ◽  
Author(s):  
Natalya Pashkova ◽  
Liping Yu ◽  
Nicholas J. Schnicker ◽  
Chun-Che Tseng ◽  
Lokesh Gakhar ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Molecular Mechanism ◽  
Structural Basis ◽  
Multivesicular Bodies ◽  
Membrane Remodeling ◽  
Endosomal Sorting ◽  
Aaa Atpase ◽  
Ubiquitinated Proteins ◽  
The Family ◽  
Ubiquitin Binding

The family of Bro1 proteins coordinates the activity of the Endosomal Sorting Complexes Required for Transport (ESCRTs) to mediate a number of membrane remodeling events. These events culminate in membrane scission catalyzed by ESCRT-III, whose polymerization and disassembly is controlled by the AAA-ATPase, Vps4. Bro1-family members Alix and HD-PTP as well as yeast Bro1 have a central ‘V’ domains that non-covalently bind Ub and connect ubiquitinated proteins to ESCRT-driven functions such as the incorporation of ubiquitinated membrane proteins into intralumenal vesicles of multivesicular bodies. Recently, it was discovered that the V domain of yeast Bro1 binds the MIT domain of Vps4 to stimulate its ATPase activity. Here we determine the structural basis for how the V domain of human HD-PTP binds ubiquitin. The HD-PTP V domain also binds the MIT domain of Vps4 and ubiquitin-binding to the HD-PTP V domain enhances its ability to stimulate Vps4 ATPase activity. Additionally, we found V domains of both HD-PTP and Bro1 bind CHMP5 and Vps60, respectively, providing another potential molecular mechanism to alter Vps4 activity. These data support a model whereby contacts between ubiquitin, ESCRT-III, and Vps4 by V domains of the Bro1 family may coordinate late events in ESCRT-driven membrane remodeling events.

scholarly journals Hrs regulates multivesicular body formation via ESCRT recruitment to endosomes

2003 ◽  
Vol 162 (3) ◽  
pp. 435-442 ◽  
Author(s):  
Kristi G. Bache ◽  
Andreas Brech ◽  
Anja Mehlum ◽  
Harald Stenmark
Keyword(s):  
Membrane Proteins ◽  
Rna Viruses ◽  
Multivesicular Body ◽  
Viral Proteins ◽  
Multivesicular Bodies ◽  
Body Formation ◽  
Endosomal Sorting ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Endosomal Vesicles

Hrs and the endosomal sorting complexes required for transport, ESCRT-I, -II, and -III, are involved in the endosomal sorting of membrane proteins into multivesicular bodies and lysosomes or vacuoles. The ESCRT complexes are also required for formation of intraluminal endosomal vesicles and for budding of certain enveloped RNA viruses such as HIV. Here, we show that Hrs binds to the ESCRT-I subunit Tsg101 via a PSAP motif that is conserved in Tsg101-binding viral proteins. Depletion of Hrs causes a reduction in membrane-associated ESCRT-I subunits, a decreased number of multivesicular bodies and an increased size of late endosomes. Even though Hrs mainly localizes to early endosomes and Tsg101 to late endosomes, the two proteins colocalize on a subpopulation of endosomes that contain lyso-bisphosphatidic acid. Overexpression of Hrs causes accumulation of Tsg101 on early endosomes and prevents its localization to late endosomes. We conclude that Hrs mediates the initial recruitment of ESCRT-I to endosomes and, thereby, indirectly regulates multivesicular body formation.

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