Role of Ubiquitylation in Cellular Membrane Transport

2006 ◽  
Vol 86 (2) ◽  
pp. 669-707 ◽  
Author(s):  
Olivier Staub ◽  
Daniela Rotin
Keyword(s):  
Membrane Proteins ◽  
Mammalian Cells ◽  
Secretory Pathway ◽  
Surface Expression ◽  
Cellular Membrane ◽  
Cell Surface Expression ◽  
Multivesicular Bodies ◽  
The Past ◽  
Endoplasmic Reticulum Associated Degradation

Ubiquitylation of membrane proteins has gained considerable interest in recent years. It has been recognized as a signal that negatively regulates the cell surface expression of many plasma membrane proteins both in yeast and in mammalian cells. Moreover, it is also involved in endoplasmic reticulum-associated degradation of membrane proteins, and it acts as a sorting signal both in the secretory pathway and in endosomes, where it targets proteins into multivesicular bodies in the lumen of vacuoles/lysosomes. In this review we discuss the progress in understanding these processes, achieved during the past several years.

scholarly journals BRET sensors unravel that Plasmodium falciparum serpentine receptor 12 (PfSR12) increases surface expression of mammalian GPCRs in HEK293 cells

2020 ◽  
Author(s):  
Pedro H. S. Pereira ◽  
Gabriela Brito ◽  
Miriam S. Moraes ◽  
Camila L. Kiyan ◽  
Charlotte Avet ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Mammalian Cells ◽  
Circulatory System ◽  
Resonance Energy ◽  
Public Health Problem ◽  
Surface Expression ◽  
Hek293 Cells ◽  
Cell Surface Expression ◽  
Thrombin Receptor

ABSTRACTMalaria causes millions of deaths worldwide and is considered a huge public health problem for underdeveloped countries. The most severe cases of malaria present complications of the host circulatory system, which may cause clogging and rupture of blood vessels, leading to death or important sequelae. Because of the previously suggested role of thrombin and platelet aggregation in Plasmodium falciparum biology, we hypothesized that one of the GPCR-like proteins identified in the genome of the parasite, P. falciparum serpentine receptor 12 (PfSR12), could be a thrombin-activated GPCR. To test this hypothesis we used a series of Bioluminescence and Bioluminescence Resonance Energy Transfer (BRET)-based biosensors to investigate the signaling activity of PfSR12. Using an Obelin based biosensor, thrombin promoted a PfSR12-dependent cytosolic Ca2+ rise in HEK293 cells. This Ca2+ mobilization was accompanied by DAG formation and PKC activation as detected using DAG and PKC BRET-based biosensors indicating a Gq/PLC/IP3 signaling pathway. The role of Gq was confirm using Gq/11 knockout HEK293 cells as well as the Gq-selective inhibitor, YM254890. Further investigation revealed that PfSR12 is not itself a thrombin receptor but rather promotes the increase of cell surface expression of an endogenous thrombin receptor. This chaperone-like effect was not selective for thrombin receptors as PfSR12 expression also promoted an increased muscarinic type 3 receptor (M3R)-promoted DAG and PKC responses. This increase response was accompanied by an increase in surface expression of M3R. Our data indicate that PfSR12 acts as a chaperone and increases the expression of several GPCRs resulting in increased responsiveness to various hormones of mammalian cells that could contribute to the deleterious effects of Plasmodium falciparum infection.

scholarly journals δ-COP modulates Aβ peptide formation via retrograde trafficking of APP

2016 ◽  
Vol 113 (19) ◽  
pp. 5412-5417 ◽  
Author(s):  
Karima Bettayeb ◽  
Jerry C. Chang ◽  
Wenjie Luo ◽  
Suvekshya Aryal ◽  
Dante Varotsis ◽  
...  
Keyword(s):  
Secretory Pathway ◽  
Amyloid Β ◽  
Retrograde Transport ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Aβ Peptide ◽  
Early Secretory Pathway ◽  
Peptide Formation ◽  
App Metabolism

The components involved in cellular trafficking and protein recycling machinery that have been associated with increased Alzheimer’s disease (AD) risk belong to the late secretory compartments for the most part. Here, we hypothesize that these late unavoidable events might be the consequence of earlier complications occurring while amyloid precursor protein (APP) is trafficking through the early secretory pathway. We investigated the relevance to AD of coat protein complex I (COPI)-dependent trafficking, an early step in Golgi-to-endoplasmic reticulum (ER) retrograde transport and one of the very first trafficking steps. Using a complex set of imaging technologies, including inverse fluorescence recovery after photobleaching (iFRAP) and photoactivatable probes, coupled to biochemical experiments, we show that COPI subunit δ (δ-COP) affects the biology of APP, including its subcellular localization and cell surface expression, its trafficking, and its metabolism. These findings demonstrate the crucial role of δ-COP in APP metabolism and, consequently, the generation of amyloid-β (Aβ) peptide, providing previously nondescribed mechanistic explanations of the underlying events.

scholarly journals Regulation of the Expression, Oligomerisation and Signaling of the Inhibitory Receptor CLEC12A by Cysteine Residues in the Stalk Region

2021 ◽  
Vol 22 (19) ◽  
pp. 10207
Author(s):  
Julien Vitry ◽  
Guillaume Paré ◽  
Andréa Murru ◽  
Xavier Charest-Morin ◽  
Halim Maaroufi ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Activation ◽  
Secretory Pathway ◽  
Surface Expression ◽  
Site Directed Mutagenesis ◽  
Cell Surface Expression ◽  
Dependent Manner ◽  
Inhibitory Receptor ◽  
Lectin Receptors ◽  
Stalk Domain

CLEC12A is a myeloid inhibitory receptor that negatively regulates inflammation in mouse models of autoimmune and autoinflammatory arthritis. Reduced CLEC12A expression enhances myeloid cell activation and inflammation in CLEC12A knock-out mice with collagen antibody-induced or gout-like arthritis. Similarly to other C-type lectin receptors, CLEC12A harbours a stalk domain between its ligand binding and transmembrane domains. While it is presumed that the cysteines in the stalk domain have multimerisation properties, their role in CLEC12A expression and/or signaling remain unknown. We thus used site-directed mutagenesis to determine whether the stalk domain cysteines play a role in CLEC12A expression, internalisation, oligomerisation, and/or signaling. Mutation of C118 blocks CLEC12A transport through the secretory pathway diminishing its cell-surface expression. In contrast, mutating C130 does not affect CLEC12A cell-surface expression but increases its oligomerisation, inducing ligand-independent phosphorylation of the receptor. Moreover, we provide evidence that CLEC12A dimerisation is regulated in a redox-dependent manner. We also show that antibody-induced CLEC12A cross-linking induces flotillin oligomerisation in insoluble membrane domains in which CLEC12A signals. Taken together, these data indicate that the stalk cysteines in CLEC12A differentially modulate this inhibitory receptor’s expression, oligomerisation and signaling, suggestive of the regulation of CLEC12A in a redox-dependent manner during inflammation.

scholarly journals Analysis of the Role of N-Linked Glycosylation in Cell Surface Expression, Function, and Binding Properties of SARS-CoV-2 Receptor ACE2

2021 ◽  
Author(s):  
Raymond Rowland ◽  
Alberto Brandariz-Nuñez
Keyword(s):  
Cell Surface ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Receptor Interaction ◽  
Minimal Effect ◽  
Binding Properties ◽  
Virus Receptor

Understanding the role of glycosylation in the virus-receptor interaction is important for developing approaches that disrupt infection. In this study, we showed that deglycosylation of both ACE2 and S had a minimal effect on the spike-ACE2 interaction.

Peroxisomal membrane proteins are properly targeted to peroxisomes in the absence of COPI- and COPII-mediated vesicular transport

2001 ◽  
Vol 114 (11) ◽  
pp. 2199-2204 ◽  
Author(s):  
Tineke Voorn-Brouwer ◽  
Astrid Kragt ◽  
Henk F. Tabak ◽  
Ben Distel
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Secretory Pathway ◽  
Human Fibroblasts ◽  
Vesicle Transport ◽  
Peroxisome Biogenesis ◽  
Peroxisomal Membrane ◽  
Classic Model ◽  
Early Secretory Pathway

The classic model for peroxisome biogenesis states that new peroxisomes arise by the fission of pre-existing ones and that peroxisomal matrix and membrane proteins are recruited directly from the cytosol. Recent studies challenge this model and suggest that some peroxisomal membrane proteins might traffic via the endoplasmic reticulum to peroxisomes. We have studied the trafficking in human fibroblasts of three peroxisomal membrane proteins, Pex2p, Pex3p and Pex16p, all of which have been suggested to transit the endoplasmic reticulum before arriving in peroxisomes. Here, we show that targeting of these peroxisomal membrane proteins is not affected by inhibitors of COPI and COPII that block vesicle transport in the early secretory pathway. Moreover, we have obtained no evidence for the presence of these peroxisomal membrane proteins in compartments other than peroxisomes and demonstrate that COPI and COPII inhibitors do not affect peroxisome morphology or integrity. Together, these data fail to provide any evidence for a role of the endoplasmic reticulum in peroxisome biogenesis.

scholarly journals IRE1α kinase–mediated unconventional protein secretion rescues misfolded CFTR and pendrin

2020 ◽  
Vol 6 (8) ◽  
pp. eaax9914
Author(s):  
Hak Park ◽  
Dong Hoon Shin ◽  
Ju-Ri Sim ◽  
Sowon Aum ◽  
Min Goo Lee
Keyword(s):  
Cell Surface ◽  
Protein Secretion ◽  
Protein Misfolding ◽  
Mammalian Cells ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Downstream Effector ◽  
Mouse Colon ◽  
Δf508 Cftr ◽  
Kinase Pathway

The most prevalent pathogenic mutations in the CFTR (ΔF508) and SLC26A4/pendrin (p.H723R), which cause cystic fibrosis and congenital hearing loss, respectively, evoke protein misfolding and subsequent defects in their cell surface trafficking. Here, we report that activation of the IRE1α kinase pathway can rescue the cell surface expression of ΔF508-CFTR and p.H723R-pendrin through a Golgi-independent unconventional protein secretion (UPS) route. In mammalian cells, inhibition of IRE1α kinase, but not inhibition of IRE1α endonuclease and the downstream effector XBP1, inhibited CFTR UPS. Treatment with the IRE1α kinase activator, (E)-2-(2-chlorostyryl)-3,5,6-trimethyl-pyrazine (CSTMP), rescued cell surface expression and functional activity of ΔF508-CFTR and p.H723R-pendrin. Treatment with a nontoxic dose of CSTMP to ΔF508-CFTR mice restored CFTR surface expression and CFTR-mediated anion transport in the mouse colon. These findings suggest that UPS activation via IRE1α kinase is a strategy to treat diseases caused by defective cell surface trafficking of membrane proteins, including ΔF508-CFTR and p.H723R-pendrin.

scholarly journals Radical and lunatic fringes modulate notch ligands to support mammalian intestinal homeostasis

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Preetish Kadur Lakshminarasimha Murthy ◽  
Tara Srinivasan ◽  
Matthew S Bochter ◽  
Rui Xi ◽  
Anastasia Kristine Varanko ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Secretory Cells ◽  
Notch Activity ◽  
Crypt Base ◽  
Notch Ligands ◽  
Cell Zone

Notch signalling maintains stem cell regeneration at the mouse intestinal crypt base and balances the absorptive and secretory lineages in the upper crypt and villus. Here we report the role of Fringe family of glycosyltransferases in modulating Notch activity in the two compartments. At the crypt base, RFNG is enriched in the Paneth cells and increases cell surface expression of DLL1 and DLL4. This promotes Notch activity in the neighbouring Lgr5+ stem cells assisting their self-renewal. Expressed by various secretory cells in the upper crypt and villus, LFNG promotes DLL surface expression and suppresses the secretory lineage . Hence, in the intestinal epithelium, Fringes are present in the ligand-presenting ‘sender’ secretory cells and promote Notch activity in the neighbouring ‘receiver’ cells. Fringes thereby provide for targeted modulation of Notch activity and thus the cell fate in the stem cell zone, or the upper crypt and villus.

Physiological significance of volume-regulatory transporters

1999 ◽  
Vol 276 (5) ◽  
pp. C995-C1011 ◽  
Author(s):  
W. Charles O’Neill
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Mammalian Cells ◽  
Ion Transporters ◽  
Subsequent Growth ◽  
The Past ◽  
Shrinkage And Swelling ◽  
Acute Changes

Research over the past 25 years has identified specific ion transporters and channels that are activated by acute changes in cell volume and that serve to restore steady-state volume. The mechanism by which cells sense changes in cell volume and activate the appropriate transporters remains a mystery, but recent studies are providing important clues. A curious aspect of volume regulation in mammalian cells is that it is often absent or incomplete in anisosmotic media, whereas complete volume regulation is observed with isosmotic shrinkage and swelling. The basis for this may lie in an important role of intracellular Cl− in controlling volume-regulatory transporters. This is physiologically relevant, since the principal threat to cell volume in vivo is not changes in extracellular osmolarity but rather changes in the cellular content of osmotically active molecules. Volume-regulatory transporters are also closely linked to cell growth and metabolism, producing requisite changes in cell volume that may also signal subsequent growth and metabolic events. Thus, despite the relatively constant osmolarity in mammals, volume-regulatory transporters have important roles in mammalian physiology.

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