scholarly journals ESCRTs function directly on the lysosome membrane to downregulate ubiquitinated lysosomal membrane proteins

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Lu Zhu ◽  
Jeff R Jorgensen ◽  
Ming Li ◽  
Ya-Shan Chuang ◽  
Scott D Emr
Keyword(s):  
Membrane Proteins ◽  
Underlying Mechanism ◽  
Genetic Screens ◽  
Vacuole Membrane ◽  
Cargo Delivery ◽  
Ubiquitin Ligase Complex ◽  
Lysosomal Membrane Proteins ◽  
Homeostasis Regulation ◽  
Nutrient Homeostasis ◽  
Cargo Sorting

The lysosome plays an important role in maintaining cellular nutrient homeostasis. Regulation of nutrient storage can occur by the ubiquitination of certain transporters that are then sorted into the lysosome lumen for degradation. To better understand the underlying mechanism of this process, we performed genetic screens to identify components of the sorting machinery required for vacuole membrane protein degradation. These screens uncovered genes that encode a ubiquitin ligase complex, components of the PtdIns 3-kinase complex, and the ESCRT machinery. We developed a novel ubiquitination system, Rapamycin-Induced Degradation (RapiDeg), to test the sorting defects caused by these mutants. These tests revealed that ubiquitinated vacuole membrane proteins recruit ESCRTs to the vacuole surface, where they mediate cargo sorting and direct cargo delivery into the vacuole lumen. Our findings demonstrate that the ESCRTs can function at both the late endosome and the vacuole membrane to mediate cargo sorting and intra-luminal vesicle formation.

scholarly journals Membrane-anchored ubiquitin ligase complex is required for the turnover of lysosomal membrane proteins

2015 ◽  
Vol 211 (3) ◽  
pp. 639-652 ◽  
Author(s):  
Ming Li ◽  
Tatsuhiro Koshi ◽  
Scott D. Emr
Keyword(s):  
Membrane Proteins ◽  
Ubiquitin Ligase ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Interacting Proteins ◽  
Vacuole Membrane ◽  
Ubiquitin Ligase Complex ◽  
Storage Organelle ◽  
Lysosomal Membrane Proteins ◽  
Nutrient Homeostasis

Cells must regulate the abundance and activity of numerous nutrient transporters in different organelle membranes to achieve nutrient homeostasis. As the recycling center and major storage organelle, lysosomes are essential for maintaining nutrient homeostasis. However, very little is known about mechanisms that govern the regulation of its membrane proteins. In this study, we demonstrated that changes of Zn2+ levels trigger the downregulation of vacuolar Zn2+ transporters. Low Zn2+ levels cause the degradation of the influx transporter Cot1, whereas high Zn2+ levels trigger the degradation of the efflux channel Zrt3. The degradation process depends on the vacuole membrane recycling and degradation pathway. Unexpectedly, we identified a RING domain–containing E3 ligase Tul1 and its interacting proteins in the Dsc complex that are important for the ubiquitination of Cot1 and partial ubiquitination of Zrt3. Our study demonstrated that the Dsc complex can function at the vacuole to regulate the composition and lifetime of vacuolar membrane proteins.

scholarly journals Recruitment and organization of ESCRT-0 and ubiquitinated cargo via condensation

2021 ◽  
Author(s):  
Sudeep Banjade ◽  
Lu Zhu ◽  
Jeffrey Jorgensen ◽  
Sho Suzuki ◽  
Scott D. Emr
Keyword(s):  
Membrane Proteins ◽  
Self Assembly ◽  
Cell Biology ◽  
Substrate Recognition ◽  
Initial Step ◽  
Binding Interactions ◽  
Vacuole Membrane ◽  
Multivalent Interactions ◽  
Cargo Sorting

AbstractThe general mechanisms by which ESCRTs are specifically recruited to various membranes, and how ESCRT subunits are spatially organized remain central questions in cell biology. At the endosome and lysosomes, ubiquitination of membrane proteins triggers ESCRT-mediated substrate recognition and degradation. Using the yeast lysosome/vacuole, we define the principles by which substrate engagement by ESCRTs occurs at this organelle. We find that multivalent interactions between ESCRT-0 and polyubiquitin is critical for substrate recognition at yeast vacuoles, with a lower-valency requirement for cargo engagement at endosomes. Direct recruitment of ESCRT-0 induces dynamic foci on the vacuole membrane, and forms fluid condensates in vitro with polyubiquitin. We propose that self-assembly of early ESCRTs induces condensation, an initial step in ESCRT-assembly/nucleation at membranes. This property can be tuned specifically at various organelles by modulating the number of binding interactions.One-Sentence SummaryCondensation of multivalent ESCRT-0/polyubiquitin assemblies organizes cargo sorting reactions at lysosomes

scholarly journals A  conserved ubiquitin- and ESCRT-dependent pathway internalizes human lysosomal membrane proteins for degradation

PLoS Biology ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. e3001361
Author(s):  
Weichao Zhang ◽  
Xi Yang ◽  
Liang Chen ◽  
Yun-Yu Liu ◽  
Varsha Venkatarangan ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Lysosomal Membrane ◽  
Dependent Manner ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Lysosomal Membrane Proteins ◽  
Carboxyl Terminal ◽  
Nutrient Homeostasis ◽  
Lysosome Membrane ◽  
Dependent Pathway

The lysosome is an essential organelle to recycle cellular materials and maintain nutrient homeostasis, but the mechanism to down-regulate its membrane proteins is poorly understood. In this study, we performed a cycloheximide (CHX) chase assay to measure the half-lives of approximately 30 human lysosomal membrane proteins (LMPs) and identified RNF152 and LAPTM4A as short-lived membrane proteins. The degradation of both proteins is ubiquitin dependent. RNF152 is a transmembrane E3 ligase that ubiquitinates itself, whereas LAPTM4A uses its carboxyl-terminal PY motifs to recruit NEDD4-1 for ubiquitination. After ubiquitination, they are internalized into the lysosome lumen by the endosomal sorting complexes required for transport (ESCRT) machinery for degradation. Strikingly, when ectopically expressed in budding yeast, human RNF152 is still degraded by the vacuole (yeast lysosome) in an ESCRT-dependent manner. Thus, our study uncovered a conserved mechanism to down-regulate lysosome membrane proteins.

scholarly journals A conserved ubiquitin- and ESCRT-dependent pathway to regulate human lysosomal membrane proteins

2020 ◽  
Author(s):  
Weichao Zhang ◽  
Xi Yang ◽  
Liang Chen ◽  
Yun-Yu Liu ◽  
Varsha Venkatarangan ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Cellular Materials ◽  
Lysosomal Membrane ◽  
Dependent Manner ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Lysosomal Membrane Proteins ◽  
Nutrient Homeostasis ◽  
Lysosome Membrane ◽  
Dependent Pathway

AbstractThe lysosome is an essential organelle to recycle cellular materials and maintain nutrient homeostasis, but the mechanism to down-regulate lysosomal membrane proteins is poorly understood. In this study, we developed a cycloheximide chase assay to measure the half-lives of ~30 human lysosomal membrane proteins, and identified RNF152 as a short-lived protein. The degradation of RNF152 depends on ubiquitin and the endosomal sorting complexes required for transport (ESCRT) machinery. Ubiquitinated RNF152 is sorted and internalized by the ESCRT machinery into the lysosomal lumen for degradation. Strikingly, when expressed in budding yeast, human RNF152 is also degraded by the vacuole (yeast lysosome) in an ESCRT-dependent manner. Thus, our study uncovered a conserved mechanism to down-regulate lysosome membrane proteins.

Lysosomal membrane proteins exposed to melanin in melanocyte B16F10

2016 ◽  
Vol 8 (3) ◽  
pp. 253-257
Author(s):  
Seung Hyuck Bang ◽  
Dong Jun Park ◽  
Yang-Hoon Kim ◽  
Jiho Min
Keyword(s):  
Membrane Proteins ◽  
Lysosomal Membrane ◽  
Lysosomal Membrane Proteins

scholarly journals NCU-G1 is a highly glycosylated integral membrane protein of the lysosome

2009 ◽  
Vol 422 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Oliver Schieweck ◽  
Markus Damme ◽  
Bernd Schröder ◽  
Andrej Hasilik ◽  
Bernhard Schmidt ◽  
...  
Keyword(s):  
Amino Acid ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Mouse Liver ◽  
Lysosomal Membrane ◽  
Molecular Forms ◽  
Type I ◽  
Calculated Molecular Mass ◽  
Sorting Motif ◽  
Lysosomal Membrane Proteins

Until recently, a modest number of approx. 40 lysosomal membrane proteins had been identified and even fewer were characterized in their function. In a proteomic study, using lysosomal membranes from human placenta we identified several candidate lysosomal membrane proteins and proved the lysosomal localization of two of them. In the present study, we demonstrate the lysosomal localization of the mouse orthologue of the human C1orf85 protein, which has been termed kidney-predominant protein NCU-G1 (GenBank® accession number: AB027141). NCU-G1 encodes a 404 amino acid protein with a calculated molecular mass of 39 kDa. The bioinformatics analysis of its amino acid sequence suggests it is a type I transmembrane protein containing a single tyrosine-based consensus lysosomal sorting motif at position 400 within the 12-residue C-terminal tail. Its lysosomal localization was confirmed using immunofluorescence with a C-terminally His-tagged NCU-G1 and the lysosomal marker LAMP-1 (lysosome-associated membrane protein-1) as a reference, and by subcellular fractionation of mouse liver after a tyloxapol-induced density shift of the lysosomal fraction using an anti-NCU-G1 antiserum. In transiently transfected HT1080 and HeLa cells, the His-tagged NCU-G1 was detected in two molecular forms with apparent protein sizes of 70 and 80 kDa, and in mouse liver the endogenous wild-type NCU-G1 was detected as a 75 kDa protein. The remarkable difference between the apparent and the calculated molecular masses of NCU-G1 was shown, by digesting the protein with N-glycosidase F, to be due to an extensive glycosylation. The lysosomal localization was impaired by mutational replacement of an alanine residue for the tyrosine residue within the putative sorting motif.

scholarly journals pH-dependent Cargo Sorting from the Golgi

2011 ◽  
Vol 286 (12) ◽  
pp. 10058-10065 ◽  
Author(s):  
Chunjuan Huang ◽  
Amy Chang
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Atpase Activity ◽  
Secretory Pathway ◽  
Ph Dependence ◽  
Glucose Deprivation ◽  
Ph Homeostasis ◽  
Plasma Membrane Proteins ◽  
Cytosolic Ph ◽  
Cargo Sorting

The vacuolar proton-translocating ATPase (V-ATPase) plays a major role in organelle acidification and works together with other ion transporters to maintain pH homeostasis in eukaryotic cells. We analyzed a requirement for V-ATPase activity in protein trafficking in the yeast secretory pathway. Deficiency of V-ATPase activity caused by subunit deletion or glucose deprivation results in missorting of newly synthesized plasma membrane proteins Pma1 and Can1 directly from the Golgi to the vacuole. Vacuolar mislocalization of Pma1 is dependent on Gga adaptors although no Pma1 ubiquitination was detected. Proper cell surface targeting of Pma1 was rescued in V-ATPase-deficient cells by increasing the pH of the medium, suggesting that missorting is the result of aberrant cytosolic pH. In addition to mislocalization of the plasma membrane proteins, Golgi membrane proteins Kex2 and Vrg4 are also missorted to the vacuole upon loss of V-ATPase activity. Because the missorted cargos have distinct trafficking routes, we suggest a pH dependence for multiple cargo sorting events at the Golgi.

The Response of Liposomes Modified with Lysosomal Membrane Proteins to the Targeting Ability Associated with Antimicrobial Activity

2018 ◽  
Vol 14 (12) ◽  
pp. 2198-2207
Author(s):  
Seung Hyuck Bang ◽  
Ra-Mi Park ◽  
Simranjeet Singh Sekhon ◽  
Geun Woo Lee ◽  
Yang-Hoon Kim ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Membrane Proteins ◽  
Lysosomal Membrane ◽  
Lysosomal Membrane Proteins ◽  
Targeting Ability
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