scholarly journals Revealing the fate of cell surface human P-glycoprotein (ABCB1): The lysosomal degradation pathway

2015 ◽  
Vol 1853 (10) ◽  
pp. 2361-2370 ◽  
Author(s):  
Kazuhiro Katayama ◽  
Khyati Kapoor ◽  
Shinobu Ohnuma ◽  
Atish Patel ◽  
William Swaim ◽  
...  
Keyword(s):  
Cell Surface ◽  
Degradation Pathway ◽  
Lysosomal Degradation ◽  
P Glycoprotein

scholarly journals Receptor-mediated biliary transport of immunoglobulin A and asialoglycoprotein: sorting and missorting of ligands revealed by two radiolabeling methods.

1984 ◽  
Vol 98 (1) ◽  
pp. 79-89 ◽  
Author(s):  
J M Schiff ◽  
M M Fisher ◽  
B J Underdown
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Protease Inhibitor ◽  
Immunoglobulin A ◽  
Degradation Pathway ◽  
Iodine Monochloride ◽  
Lysosomal Degradation ◽  
Major Fraction ◽  
Transport Pathways ◽  
Lysosomal Protease

In the rat, all receptor-bindable immunoglobulin A (IgA), and 1-4% of injected asialoglycoprotein (ASG), are transported from blood to bile intact. The major fraction of the ASG is degraded in hepatic lysosomes. The study described here was designed to elucidate the sorting that occurs in hepatocytes subsequent to receptor binding of ligands not sharing the same fate. We show that conjugation of protein with the Bolton and Hunter reagent can be used as a probe for the lysosomal pathway, since 50% of the reagent is released into bile after lysosomal degradation of internalized protein. Radiolabeling by iodine monochloride was alternatively used to follow the direct pathways that deliver intact IgA and ASG to bile. After intravenous injection of labeled proteins, first intact ASG and IgA, and then radioactive catabolites from degraded protein, were released into bile. No proteolytic intermediates were detected, and the transport of IgA or ASG directly to bile was not affected by the lysosomal protease inhibitor leupeptin. These observations indicate that divergence of the direct biliary transport pathways from the degradation pathway occurs at a stage preceding delivery to lysosomes, possibly at the cell surface. Competition studies showed that all three pathways (including the biliary transport of intact ASG) are receptor mediated, but even at supersaturating doses the uptake and processing of IgA and ASG occur independently. We propose that IgA and ASG receptors are not frequently in juxtaposition on the plasma membrane, but that ASG, after binding to its receptor, is occasionally missorted into the biliary transport pool.

scholarly journals SNX17 protects integrins from degradation by sorting between lysosomal and recycling pathways

2012 ◽  
Vol 197 (2) ◽  
pp. 219-230 ◽  
Author(s):  
Florian Steinberg ◽  
Kate J. Heesom ◽  
Mark D. Bass ◽  
Peter J. Cullen
Keyword(s):  
Isotope Labeling ◽  
Degradation Pathway ◽  
Lysosomal Degradation ◽  
Sorting Nexins ◽  
Retromer Complex ◽  
Proteomic Approach ◽  
Cytoplasmic Tails ◽  
Npxy Motif ◽  
Global Identification ◽  
Insight Into

The FERM-like domain–containing sorting nexins of the SNX17/SNX27/SNX31 family have been proposed to mediate retrieval of transmembrane proteins from the lysosomal pathway. In this paper, we describe a stable isotope labeling with amino acids in culture–based quantitative proteomic approach that allows an unbiased, global identification of transmembrane cargoes that are rescued from lysosomal degradation by SNX17. This screen revealed that several integrins required SNX17 for their stability, as depletion of SNX17 led to a loss of β1 and β5 integrins and associated a subunits from HeLa cells as a result of increased lysosomal degradation. SNX17 bound to the membrane distal NPXY motif in β integrin cytoplasmic tails, thereby preventing lysosomal degradation of β integrins and their associated a subunits. Furthermore, SNX17-dependent retrieval of integrins did not depend on the retromer complex. Consistent with an effect on integrin recycling, depletion of SNX17 also caused alterations in cell migration. Our data provide mechanistic insight into the retrieval of internalized integrins from the lysosomal degradation pathway, a prerequisite for subsequent recycling of these matrix receptors.

Downregulation of the vasopressin type 2 receptor after vasopressin-induced internalization: involvement of a lysosomal degradation pathway

2005 ◽  
Vol 288 (6) ◽  
pp. C1390-C1401 ◽  
Author(s):  
Richard Bouley ◽  
Herbert Y. Lin ◽  
Malay K. Raychowdhury ◽  
Vladimir Marshansky ◽  
Dennis Brown ◽  
...  
Keyword(s):  
Cell Surface ◽  
Fluorescent Protein ◽  
Collecting Duct ◽  
Time Lag ◽  
Renal Medulla ◽  
Degradation Pathway ◽  
Urinary Concentration ◽  
Long Time ◽  
Green Fluorescent ◽  
Golgi Network

Vasopressin (VP) increases urinary concentration by signaling through the vasopressin receptor (V2R) in collecting duct principal cells. After downregulation, V2R reappears at the cell surface via an unusually slow (several hours) “recycling” pathway. To examine this pathway, we expressed V2R-green fluorescent protein (GFP) in LLC-PK1a cells. V2R-GFP showed characteristics similar to those of wild-type V2R, including high affinity for VP and adenylyl cyclase stimulation. V2R-GFP was located mainly in the plasma membrane in unstimulated cells, but it colocalized with the lysosomal marker Lysotracker after VP-induced internalization. Western blot analysis of V2R-GFP showed a broad 57- to 68-kDa band and a doublet at 46 and 52 kDa before VP treatment. After 4-h VP exposure, the 57- to 68-kDa band lost 50% of its intensity, whereas the lower 46-kDa band increased by 200%. The lysosomal inhibitor chloroquine abolished this VP effect, whereas lactacystin, a proteasome inhibitor, had no effect. Incubating cells at 20°C to block trafficking from the trans-Golgi network reduced V2R membrane fluorescence, and a perinuclear patch developed. Cycloheximide reduced the intensity of this patch, showing that newly synthesized V2R-GFP contributed significantly to its appearance. Cycloheximide also inhibited the reappearance of cell surface V2R after downregulation. We conclude that after downregulation, V2R-GFP is delivered to lysosomes and degraded. Reappearance of V2R at the cell surface depends on new protein synthesis, partially explaining the long time lag needed to fully reestablish V2R at the cell surface after downregulation. This degradative pathway may be an adaptive response to allow receptor-ligand association in the hypertonic and acidic environment of the renal medulla.

scholarly journals Autophagy gene-dependent intracellular immunity triggered by interferon-γ

2021 ◽  
Author(s):  
Michael R McAllaster ◽  
Jaya Bhushan ◽  
Dale R Balce ◽  
Anthony Orvedahl ◽  
Arnold Park ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Interferon Γ ◽  
Degradation Pathway ◽  
Lysosomal Degradation ◽  
Cellular Processes ◽  
Binding Domains ◽  
New Genes ◽  
Autophagy Gene ◽  
Atg Genes ◽  
Dependent Processes

Genes required for the lysosomal degradation pathway of autophagy play key roles in topologically distinct cellular processes with significant physiologic importance. One of the first-described of these ATG gene-dependent processes is the requirement for a subset of ATG genes in interferon-γ (IFNγ)-induced inhibition of Norovirus and Toxoplasma gondii replication. Herein we identified new genes that are required for or that negatively regulate this immune mechanism. Enzymes involved in the conjugation of UFM1 to target proteins including UFC1 and UBA5, negatively regulated IFNγ-induced inhibition of norovirus replication via effects of Ern1. IFNγ-induced inhibition of norovirus replication required Wipi2b and Atg9a, but not Becn1 (encoding Beclin1), Atg14, or Sqstm1. The phosphatidylinositol-3-phosphate and ATG16L1 binding domains of WIPI2B were required for IFNγ-induced inhibition of norovirus replication. Both WIPI2 and SQSTM1 were required for IFN?-induced inhibition of Toxoplasma gondii replication in HeLa cells. These studies further delineate the mechanisms of a programmable form of cytokine-induced intracellular immunity that relies on an expanding cassette of essential ATG genes to restrict the growth of phylogenetically diverse pathogens.

scholarly journals An Intervention Target for Myocardial Fibrosis: Autophagy

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Chunmiao Lu ◽  
Yusong Yang ◽  
Yaping Zhu ◽  
Shichao Lv ◽  
Junping Zhang
Keyword(s):  
Cardiovascular Diseases ◽  
Myocardial Fibrosis ◽  
Collagen Synthesis ◽  
Degradation Pathway ◽  
Lysosomal Degradation ◽  
Metabolic Imbalance

Myocardial fibrosis (MF) is the result of metabolic imbalance of collagen synthesis and metabolism, which is widespread in various cardiovascular diseases. Autophagy is a lysosomal degradation pathway which is highly conserved. In recent years, research on autophagy has been increasing and the researchers have also become cumulatively aware of the specified association between autophagy and MF. This review highlights the role of autophagy in MF and the potential effects through the administration of medicine.

Syntaxin 12 and COMMD3 are new factors that function with VPS33B in the biogenesis of platelet α-granules

Blood ◽  
2021 ◽  
Author(s):  
Andrea L Ambrosio ◽  
Hallie P Febvre ◽  
Santiago Mauro Di Pietro
Keyword(s):  
Cell Surface ◽  
Dependent Manner ◽  
Bleeding Disorders ◽  
Snare Protein ◽  
Entry And Exit ◽  
Lysosomal Degradation ◽  
Physiological Processes ◽  
Hand Off ◽  
Granule Proteins ◽  
Syntaxin 12

Platelet a-granules regulate hemostasis and myriad other physiological processes but their biogenesis is unclear. Mutations in only three proteins are known to cause a-granule defects and bleeding disorders in humans. Two such proteins, VPS16B and VPS33B, form a complex mediating transport of newly synthesized a-granule proteins through megakaryocyte endosomal compartments. It is unclear how the VPS16B/VPS33B complex accomplishes this function. Here we report VPS16B/VPS33B associates physically with Stx12, a SNARE protein that mediates vesicle fusion at endosomes. Importantly, Stx12 deficient megakaryocytes display reduced a-granule numbers and overall levels of a-granule proteins, thus revealing Stx12 as new component of the a-granule biogenesis machinery. VPS16B/VPS33B also binds CCDC22, a component of the CCC complex working at endosome exit sites. CCDC22 competes with Stx12 for binding to VPS16B/VPS33B suggesting a possible hand-off mechanism. Moreover, the major CCC form expressed in megakaryocytes contains COMMD3, one of ten COMMD proteins. Deficiency of COMMD3/CCDC22 causes reduced a-granule numbers and overall levels of a-granule proteins, establishing the COMMD3/CCC complex as a new factor in a-granule biogenesis. Furthermore, P-Selectin traffics through the cell surface in a COMMD3-dependent manner and depletion of COMMD3 results in lysosomal degradation of P-Selectin and PF4. Stx12 and COMMD3/CCC deficiency cause less severe phenotypes than VPS16B/VPS33B deficiency, suggesting Stx12 and COMMD3/CCC assist but are less important than VPS16B/VPS33B in a-granule biogenesis. Mechanistically, our results suggest VPS16B/VPS33B coordinates the endosomal entry and exit of a-granule proteins by linking the fusogenic machinery with a ubiquitous endosomal retrieval complex that is repurposed in megakaryocytes to make a-granules.

scholarly journals Autophagy Modulation in Lymphocytes From COVID-19 Patients: New Therapeutic Target in SARS-COV-2 Infection

2020 ◽  
Vol 11 ◽  
Author(s):  
Marta Vomero ◽  
Cristiana Barbati ◽  
Tania Colasanti ◽  
Alessandra Ida Celia ◽  
Mariangela Speziali ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Degradation Pathway ◽  
The Novel ◽  
Lysosomal Degradation ◽  
Tnf Α ◽  
Evolutionarily Conserved ◽  
Novel Coronavirus ◽  
Factor Α ◽  
Necrosis Factor ◽  
Pro Inflammatory Cytokines

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the novel coronavirus, causing coronavirus disease 2019 (COVID-19). During virus infection, several pro-inflammatory cytokines are produced, leading to the “cytokine storm.” Among these, interleukin (IL)-6, tumor necrosis factor‐α (TNF‐α), and IL-1β seem to have a central role in the progression and exacerbation of the disease, leading to the recruitment of immune cells to infection sites. Autophagy is an evolutionarily conserved lysosomal degradation pathway involved in different aspects of lymphocytes functionality. The involvement of IL-6, TNF‐α, and IL-1β in autophagy modulation has recently been demonstrated. Moreover, preliminary studies showed that SARS-CoV-2 could infect lymphocytes, playing a role in the modulation of autophagy. Several anti-rheumatic drugs, now proposed for the treatment of COVID-19, could modulate autophagy in lymphocytes, highlighting the therapeutic potential of targeting autophagy in SARS-CoV-2 infection.

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