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.

Structure and function of ESCRT-III

2009 ◽  
Vol 37 (1) ◽  
pp. 156-160 ◽  
Author(s):  
Suman Lata ◽  
Guy Schoehn ◽  
Julianna Solomons ◽  
Ricardo Pires ◽  
Heinrich G. Göttlinger ◽  
...  
Keyword(s):  
Multivesicular Body ◽  
Multivesicular Bodies ◽  
Tubular Structures ◽  
Body Protein ◽  
Enveloped Viruses ◽  
Endosomal Sorting ◽  
Vacuolar Protein ◽  
And Function ◽  
Endosomal Vesicles

ESCRT-III (endosomal sorting complex required for transport III) is required for the formation and abscission of intraluminal endosomal vesicles, which gives rise to multivesicular bodies, budding of some enveloped viruses and cytokinesis. ESCRT-III is composed of 11 members in humans, which, except for one, correspond to the six ESCRT-III-like proteins in yeast. At least CHMP (charged multivesicular body protein) 2A and CHMP3 assemble into helical tubular structures that provide a platform for membrane interaction and VPS (vacuolar protein sorting) 4-catalysed effects leading to disassembly of ESCRT-III CHMP2A–CHMP3 polymers in vitro. Progress towards the understanding of the structures and function of ESCRT-III, its activation, its regulation by accessory factors and its role in abscission of membrane enveloped structures in concert with VPS4 are discussed.

scholarly journals Axonal and dendritic endocytic pathways in cultured neurons.

1992 ◽  
Vol 119 (1) ◽  
pp. 123-137 ◽  
Author(s):  
R G Parton ◽  
K Simons ◽  
C G Dotti
Keyword(s):  
Cell Body ◽  
Hippocampal Neurons ◽  
Multivesicular Body ◽  
Nerve Terminals ◽  
Multivesicular Bodies ◽  
Late Endosomes ◽  
Distal Side ◽  
Early Endosomes ◽  
Fast Transport ◽  
Endocytic Pathways

The endocytic pathways from the axonal and dendritic surfaces of cultured polarized hippocampal neurons were examined. The dendrites and cell body contained extensive networks of tubular early endosomes which received endocytosed markers from the somatodendritic domain. In axons early endosomes were confined to presynaptic terminals and to varicosities. The somatodendritic but not the presynaptic early endosomes were labeled by internalized transferrin. In contrast to early endosomes, late endosomes and lysosomes were shown to be predominantly located in the cell body. Video microscopy was used to follow the transport of internalized markers from the periphery of axons and dendrites back to the cell body. Labeled structures in both domains moved unidirectionally by retrograde fast transport. Axonally transported organelles were sectioned for EM after video microscopic observation and shown to be large multivesicular body-like structures. Similar structures accumulated at the distal side of an axonal lesion. Multivesicular bodies therefore appear to be the major structures mediating transport of endocytosed markers between the nerve terminals and the cell body. Late endocytic structures were also shown to be highly mobile and were observed moving within the cell body and proximal dendritic segments. The results show that the organization of the endosomes differs in the axons and dendrites of cultured rat hippocampal neurons and that the different compartments or stages of the endocytic pathways can be resolved spatially.

scholarly journals Molecular mechanism to recruit galectin-3 into multivesicular bodies for polarized exosomal secretion

2018 ◽  
Vol 115 (19) ◽  
pp. E4396-E4405 ◽  
Author(s):  
Sebastian Bänfer ◽  
Dominik Schneider ◽  
Jenny Dewes ◽  
Maximilian T. Strauss ◽  
Sven-A. Freibert ◽  
...  
Keyword(s):  
Secretory Pathway ◽  
Direct Interaction ◽  
Multivesicular Body ◽  
Dominant Negative ◽  
Amino Terminus ◽  
Multivesicular Bodies ◽  
Dramatic Decrease ◽  
Endosomal Sorting ◽  
Galectin 3 ◽  
Binding Lectin

The beta-galactoside binding lectin galectin-3 (Gal3) is found intracellularly and in the extracellular space. Secretion of this lectin is mediated independently of the secretory pathway by a not yet defined nonclassical mechanism. Here, we found Gal3 in the lumen of exosomes. Superresolution and electron microscopy studies visualized Gal3 recruitment and sorting into intraluminal vesicles. Exosomal Gal3 release depends on the endosomal sorting complex required for transport I (ESCRT-I) component Tsg101 and functional Vps4a. Either Tsg101 knockdown or expression of dominant-negative Vps4aE228Q causes an intracellular Gal3 accumulation at multivesicular body formation sites. In addition, we identified a highly conserved tetrapeptide P(S/T)AP motif in the amino terminus of Gal3 that mediates a direct interaction with Tsg101. Mutation of the P(S/T)AP motif results in a loss of interaction and a dramatic decrease in exosomal Gal3 secretion. We conclude that Gal3 is a member of endogenous non-ESCRT proteins which are P(S/T)AP tagged for exosomal release.

scholarly journals The Yeast vps Class E Mutants: The Beginning of the Molecular Genetic Analysis of Multivesicular Body Biogenesis

2010 ◽  
Vol 21 (23) ◽  
pp. 4057-4060 ◽  
Author(s):  
Emily M. Coonrod ◽  
Tom H. Stevens
Keyword(s):  
Membrane Proteins ◽  
Molecular Genetic ◽  
Multivesicular Body ◽  
Molecular Genetic Analysis ◽  
Vacuolar Membrane ◽  
Multivesicular Bodies ◽  
Golgi Membrane ◽  
Cargo Proteins ◽  
Vacuolar Protein ◽  
Class E

In 1992, Raymond et al. published a compilation of the 41 yeast vacuolar protein sorting (vps) mutant groups and described a large class of mutants (class E vps mutants) that accumulated an exaggerated prevacuolar endosome-like compartment. Further analysis revealed that this “class E compartment” contained soluble vacuolar hydrolases, vacuolar membrane proteins, and Golgi membrane proteins unable to recycle back to the Golgi complex, yet these class E vps mutants had what seemed to be normal vacuoles. The 13 class E VPS genes were later shown to encode the proteins that make up the complexes required for formation of intralumenal vesicles in late endosomal compartments called multivesicular bodies, and for the sorting of ubiquitinated cargo proteins into these internal vesicles for eventual delivery to the vacuole or lysosome.

scholarly journals Plasma membrane deformation by circular arrays of ESCRT-III protein filaments

2008 ◽  
Vol 180 (2) ◽  
pp. 389-402 ◽  
Author(s):  
Phyllis I. Hanson ◽  
Robyn Roth ◽  
Yuan Lin ◽  
John E. Heuser
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Negative Curvature ◽  
Multivesicular Body ◽  
Multivesicular Bodies ◽  
Deficient Mutant ◽  
Membrane Deformation ◽  
Endosomal Sorting ◽  
Viral Budding ◽  
Circular Arrays

Endosomal sorting complex required for transport III (ESCRT-III) proteins function in multivesicular body biogenesis and viral budding. They are recruited from the cytoplasm to the membrane, where they assemble into large complexes. We used “deep-etch” electron microscopy to examine polymers formed by the ESCRT-III proteins hSnf7-1 (CHMP4A) and hSnf7-2 (CHMP4B). When overexpressed, these proteins target to endosomes and the plasma membrane. Both hSnf7 proteins assemble into regular approximately 5-nm filaments that curve and self-associate to create circular arrays. Binding to a coexpressed adenosine triphosphate hydrolysis–deficient mutant of VPS4B draws these filaments together into tight circular scaffolds that bend the membrane away from the cytoplasm to form buds and tubules protruding from the cell surface. Similar buds develop in the absence of mutant VPS4B when hSnf7-1 is expressed without its regulatory C-terminal domain. We demonstrate that hSnf7 proteins form novel membrane-attached filaments that can promote or stabilize negative curvature and outward budding. We suggest that ESCRT-III polymers delineate and help generate the luminal vesicles of multivesicular bodies.

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 Rapid Transport of Internalized P-Selectin to Late Endosomes and the Tgn

2000 ◽  
Vol 151 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Kimberly S. Straley ◽  
Samuel A. Green
Keyword(s):  
Cell Surface ◽  
Low Density Lipoprotein ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
Cell Surface Receptors ◽  
Surface Receptors ◽  
Endosomal Sorting ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Granule Membrane

Prior studies on receptor recycling through late endosomes and the TGN have suggested that such traffic may be largely limited to specialized proteins that reside in these organelles. We present evidence that efficient recycling along this pathway is functionally important for nonresident proteins. P-selectin, a transmembrane cell adhesion protein involved in inflammation, is sorted from recycling cell surface receptors (e.g., low density lipoprotein [LDL] receptor) in endosomes, and is transported from the cell surface to the TGN with a half-time of 20–25 min, six to seven times faster than LDL receptor. Native P-selectin colocalizes with LDL, which is efficiently transported to lysosomes, for 20 min after internalization, but a deletion mutant deficient in endosomal sorting activity rapidly separates from the LDL pathway. Thus, P-selectin is sorted from LDL receptor in early endosomes, driving P-selectin rapidly into late endosomes. P-selectin then recycles to the TGN as efficiently as other receptors. Thus, the primary effect of early endosomal sorting of P-selectin is its rapid delivery to the TGN, with rapid turnover in lysosomes a secondary effect of frequent passage through late endosomes. This endosomal sorting event provides a mechanism for efficiently recycling secretory granule membrane proteins and, more generally, for downregulating cell surface receptors.

In Vivo Multivesicular Body and Exosome Secretion in the Intestinal Epithelial Cells of Turtles During Hibernation

2019 ◽  
Vol 25 (6) ◽  
pp. 1341-1351
Author(s):  
Waseem Ali Vistro ◽  
Yufei Huang ◽  
Xuebing Bai ◽  
Ping Yang ◽  
Abdul Haseeb ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Susceptibility Gene ◽  
Multivesicular Body ◽  
Intestinal Epithelial ◽  
Transmission Electron ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Cluster Of Differentiation

AbstractThe present study was designed to investigate the in vivo biological processes of multivesicular bodies (MVBs) and exosomes in mitochondria-rich cells (MRCs), goblet cells (GCs), and absorptive cells (ACs) in turtle intestines during hibernation. The exosome markers, cluster of differentiation 63 (CD63) and tumor susceptibility gene 101 (TSG101), were positively expressed in intestinal villi during turtle hibernation. The distribution and formation processes of MVBs and exosomes in turtle MRCs, GCs, and ACs were further confirmed by transmission electron microscopy. During hibernation, abundantly secreted early endosomes (ees) were localized in the luminal and basal cytoplasm of the MRCs and ACs, and late endosomes (les) were dispersed with the supranuclear parts of the MRCs and ACs. Many “heterogeneous” MVBs were identified throughout the cytoplasm of the MRCs and ACs. Interestingly, the ees, les, and MVBs were detected in the cytoplasm of the GCs during hibernation; however, they were absent during nonhibernation. Furthermore, the exocytosis pathways of exosomes and autophagic vacuoles were observed in the MRCs, GCs, and ACs during hibernation. In addition, the number of different MVBs with intraluminal vesicles (ILVs) and heterogeneous endosome–MVB–exosome complexes was significantly increased in the MRCs, GCs, and ACs during hibernation. All these findings indicate that intestinal epithelial cells potentially perform a role in the secretion of MVBs and exosomes, which are essential for mucosal immunity, during hibernation.

scholarly journals The deubiquitinating enzyme DUB2A enhances CSF3 signalling by attenuating lysosomal routing of the CSF3 receptor

2011 ◽  
Vol 434 (2) ◽  
pp. 343-351 ◽  
Author(s):  
Annemarie Meenhuis ◽  
Carola Verwijmeren ◽  
Onno Roovers ◽  
Ivo P. Touw
Keyword(s):  
E3 Ligase ◽  
Deubiquitinating Enzyme ◽  
Deubiquitinating Enzymes ◽  
Lysosomal Degradation ◽  
Feedback Mechanisms ◽  
Endosomal Sorting ◽  
Adaptor Molecule ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Stimulating Factor

Ubiquitination of the CSF3R [CSF3 (colony-stimulating factor 3) receptor] occurs after activated CSF3Rs are internalized and reside in early endosomes. CSF3R ubiquitination is crucial for lysosomal routing and degradation. The E3 ligase SOCS3 (suppressor of cytokine signalling 3) has been shown to play a major role in this process. Deubiquitinating enzymes remove ubiquitin moieties from target proteins by proteolytic cleavage. Two of these enzymes, AMSH [associated molecule with the SH3 domain of STAM (signal transducing adaptor molecule)] and UBPY (ubiquitin isopeptidase Y), interact with the general endosomal sorting machinery. Whether deubiquitinating enzymes control CSF3R trafficking from early towards late endosomes is unknown. In the present study, we asked whether AMSH, UBPY or a murine family of deubiquitinating enzymes could fulfil such a role. This DUB family (deubiquitin enzyme family) comprises four members (DUB1, DUB1A, DUB2 and DUB2A), which were originally described as being haematopoietic-specific and cytokine-inducible, but their function in cytokine receptor routing and signalling has remained largely unknown. We show that DUB2A expression is induced by CSF3 in myeloid 32D cells and that DUB2 decreases ubiquitination and lysosomal degradation of the CSF3R, leading to prolonged signalling. These results support a model in which CSF3R ubiquitination is dynamically controlled at the early endosome by feedback mechanisms involving CSF3-induced E3 ligase (SOCS3) and deubiquitinase (DUB2A) activities.

scholarly journals SCAMP3 Negatively Regulates Epidermal Growth Factor Receptor Degradation and Promotes Receptor Recycling

2009 ◽  
Vol 20 (6) ◽  
pp. 1816-1832 ◽  
Author(s):  
Quyen L. Aoh ◽  
Anna M. Castle ◽  
Charles H. Hubbard ◽  
Osamu Katsumata ◽  
J. David Castle
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Multivesicular Bodies ◽  
Receptor Recycling ◽  
Endosomal Sorting ◽  
Accelerated Degradation ◽  
Early Endosomes ◽  
Epidermal Growth

The epidermal growth factor receptor (EGFR) is targeted for lysosomal degradation by ubiquitin-mediated interactions with the ESCRTs (endosomal-sorting complexes required for transport) in multivesicular bodies (MVBs). We show that secretory carrier membrane protein, SCAMP3, localizes in part to early endosomes and negatively regulates EGFR degradation through processes that involve its ubiquitylation and interactions with ESCRTs. SCAMP3 is multimonoubiquitylated and is able to associate with Nedd4 HECT ubiquitin ligases and the ESCRT-I subunit Tsg101 via its PY and PSAP motifs, respectively. SCAMP3 also associates with the ESCRT-0 subunit Hrs. Depletion of SCAMP3 in HeLa cells by inhibitory RNA accelerated degradation of EGFR and EGF while inhibiting recycling. Conversely, overexpression enhanced EGFR recycling unless ubiquitylatable lysines, PY or PSAP motifs in SCAMP3 were mutated. Notably, dual depletions of SCAMP3 and ESCRT subunits suggest that SCAMP3 has a distinct function in parallel with the ESCRTs that regulates receptor degradation. This function may affect trafficking of receptors from prelysosomal compartments as SCAMP3 depletion appeared to sustain the incidence of EGFR-containing MVBs detected by immunoelectron microscopy. Together, our results suggest that SCAMP3, its modification with ubiquitin, and its interactions with ESCRTs coordinately regulate endosomal pathways and affect the efficiency of receptor down-regulation.

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