γ-Interferon decreases the level of 26S proteasomes and changes the pattern of phosphorylation

2001 ◽  
Vol 353 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Suchira BOSE ◽  
Paul BROOKS ◽  
Grant G. F. MASON ◽  
A.Jennifer RIVETT
Keyword(s):  
Mammalian Cells ◽  
Antigen Processing ◽  
Interferon Γ ◽  
26S Proteasome ◽  
Lysosomal Degradation ◽  
Intracellular Proteins ◽  
Different Types ◽  
Proteasome Subunits ◽  
Ifn Treatment ◽  
Γ Interferon

In mammalian cells proteasomes can be activated by two different types of regulatory complexes which bind to the ends of the proteasome cylinder. Addition of two 19S (PA700; ATPase) complexes forms the 26S proteasome, which is responsible for ATP-dependent non-lysosomal degradation of intracellular proteins, whereas 11S complexes (PA28; REG) have been implicated in antigen processing. The PA28 complex is upregulated in response to γ-interferon (γ-IFN) as are three non-essential subunits of the 20S proteasome. In the present study we have investigated the effects of γ-IFN on the level of different proteasome complexes and on the phosphorylation of proteasome subunits. After treatment of cells with γ-IFN, the level of 26S proteasomes decreased and there was a concomitant increase in PA28Őproteasome complexes. However, no free 19S regulatory complexes were detected. The majority of the γ-IFN-inducible proteasome subunits LMP2 and LMP7 were present in PA28Őproteasome complexes, but these subunits were also found in 26S proteasomes. The level of phosphorylation of both 20S and 26S proteasome subunits was found to decrease after γ-IFN treatment of cells. The C8 alpha subunit showed more than a 50% decrease in phosphorylation, and the phosphorylation of C9 was only barely detectable after γ-IFN treatment. These results suggest that association of regulatory components to 20S proteasomes is regulated, and that phosphorylation of proteasome alpha subunits may be one mode of regulation.

scholarly journals Subcellular localization of proteasomes and their regulatory complexes in mammalian cells

2000 ◽  
Vol 346 (1) ◽  
pp. 155-161 ◽  
Author(s):  
Paul BROOKS ◽  
Graciela FUERTES ◽  
Rachael Z. MURRAY ◽  
Suchira BOSE ◽  
Erwin KNECHT ◽  
...  
Keyword(s):  
Rat Liver ◽  
Subcellular Distribution ◽  
Mammalian Cells ◽  
Antigen Processing ◽  
Cultured Cells ◽  
26S Proteasome ◽  
Molecular Forms ◽  
20S Proteasome ◽  
Obvious Effect ◽  
Γ Interferon

Proteasomes can exist in several different molecular forms in mammalian cells. The core 20S proteasome, containing the proteolytic sites, binds regulatory complexes at the ends of its cylindrical structure. Together with two 19S ATPase regulatory complexes it forms the 26S proteasome, which is involved in ubiquitin-dependent proteolysis. The 20S proteasome can also bind 11S regulatory complexes (REG, PA28) which play a role in antigen processing, as do the three variable γ-interferon-inducible catalytic β-subunits (e.g. LMP7). In the present study, we have investigated the subcellular distribution of the different forms of proteasomes using subunit specific antibodies. Both 20S proteasomes and their 19S regulatory complexes are found in nuclear, cytosolic and microsomal preparations isolated from rat liver. LMP7 was enriched approximately two-fold compared with core α-type proteasome subunits in the microsomal preparations. 20S proteasomes were more abundant than 26S proteasomes, both in liver and cultured cell lines. Interestingly, some significant differences were observed in the distribution of different subunits of the 19S regulatory complexes. S12, and to a lesser extent p45, were found to be relatively enriched in nuclear fractions from rat liver, and immunofluorescent labelling of cultured cells with anti-p45 antibodies showed stronger labelling in the nucleus than in the cytoplasm. The REG was found to be localized predominantly in the cytoplasm. Three- to six-fold increases in the level of REG were observed following γ-interferon treatment of cultured cells but γ-interferon had no obvious effect on its subcellular distribution. These results demonstrate that different regulatory complexes and subpopulations of proteasomes have different distributions within mammalian cells and, therefore, that the distribution is more complex than has been reported for yeast proteasomes.

scholarly journals Phosphorylation of 20S proteasome alpha subunit C8 (alpha7) stabilizes the 26S proteasome and plays a role in the regulation of proteasome complexes by gamma-interferon

2004 ◽  
Vol 378 (1) ◽  
pp. 177-184 ◽  
Author(s):  
Suchira BOSE ◽  
Fiona L. L. STRATFORD ◽  
Kerry I. BROADFOOT ◽  
Grant G. F. MASON ◽  
A. Jennifer RIVETT
Keyword(s):  
Mammalian Cells ◽  
Substantial Effect ◽  
26S Proteasome ◽  
20S Proteasome ◽  
Phosphorylation Sites ◽  
Animal Cells ◽  
Catalytic Subunits ◽  
Kinase Ck2 ◽  
Γ Interferon

In animal cells there are several regulatory complexes which interact with 20S proteasomes and give rise to functionally distinct proteasome complexes. γ-Interferon upregulates three immuno beta catalytic subunits of the 20S proteasome and the PA28 regulator, and decreases the level of 26S proteasomes. It also decreases the level of phosphorylation of two proteasome alpha subunits, C8 (α7) and C9 (α3). In the present study we have investigated the role of phosphorylation of C8 by protein kinase CK2 in the formation and stability of 26S proteasomes. An epitope-tagged C8 subunit expressed in mammalian cells was efficiently incorporated into both 20S proteasomes and 26S proteasomes. Investigation of mutants of C8 at the two known CK2 phosphorylation sites demonstrated that these are the two phosphorylation sites of C8 in animal cells. Although phosphorylation of C8 was not absolutely essential for the formation of 26S proteasomes, it did have a substantial effect on their stability. Also, when cells were treated with γ-interferon, there was a marked decrease in phosphorylation of C8, a decrease in the level of 26S proteasomes, and an increase in immunoproteasomes and PA28 complexes. These results suggest that the down-regulation of 26S proteasomes after γ-interferon treatment results from the destabilization that occurs after dephosphorylation of the C8 subunit.

scholarly journals Replacement of proteasome subunits X and Y by LMP7 and LMP2 induced by interferon-γ for acquirement of the functional diversity responsible for antigen processing

FEBS Letters ◽  
1994 ◽  
Vol 343 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Kinya Akiyama ◽  
Susumu Kagawa ◽  
Tomohiro Tamura ◽  
Naoki Shimbara ◽  
Makoto Takashina ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Antigen Processing ◽  
Interferon Γ ◽  
Proteasome Subunits

scholarly journals Lipid disequilibrium disrupts ER proteostasis by impairing ERAD substrate glycan trimming and dislocation

2017 ◽  
Vol 28 (2) ◽  
pp. 270-284 ◽  
Author(s):  
Milton To ◽  
Clark W. H. Peterson ◽  
Melissa A. Roberts ◽  
Jessica L. Counihan ◽  
Tiffany T. Wu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Mammalian Cells ◽  
26S Proteasome ◽  
Unfolded Protein ◽  
Acid Analogue ◽  
Triacsin C ◽  
Chain Acyl ◽  
Dependent Cell ◽  
Outstanding Question ◽  
The Unfolded Protein Response

The endoplasmic reticulum (ER) mediates the folding, maturation, and deployment of the secretory proteome. Proteins that fail to achieve their native conformation are retained in the ER and targeted for clearance by ER-associated degradation (ERAD), a sophisticated process that mediates the ubiquitin-dependent delivery of substrates to the 26S proteasome for proteolysis. Recent findings indicate that inhibition of long-chain acyl-CoA synthetases with triacsin C, a fatty acid analogue, impairs lipid droplet (LD) biogenesis and ERAD, suggesting a role for LDs in ERAD. However, whether LDs are involved in the ERAD process remains an outstanding question. Using chemical and genetic approaches to disrupt diacylglycerol acyltransferase (DGAT)–dependent LD biogenesis, we provide evidence that LDs are dispensable for ERAD in mammalian cells. Instead, our results suggest that triacsin C causes global alterations in the cellular lipid landscape that disrupt ER proteostasis by interfering with the glycan trimming and dislocation steps of ERAD. Prolonged triacsin C treatment activates both the IRE1 and PERK branches of the unfolded protein response and ultimately leads to IRE1-dependent cell death. These findings identify an intimate relationship between fatty acid metabolism and ER proteostasis that influences cell viability.

Electropermeabilization and Electrosensitivity of Different Types of Mammalian Cells

1989 ◽  
pp. 319-330 ◽  
Author(s):  
M. J. O’Hare ◽  
M. G. Ormerod ◽  
P. R. Imrie ◽  
J. H. Peacock ◽  
W. Asche
Keyword(s):  
Mammalian Cells ◽  
Different Types

A novel protein complex involved in signal transduction possessing similarities to 26S proteasome subunits

1998 ◽  
Vol 12 (6) ◽  
pp. 469-478 ◽  
Author(s):  
Michael Seeger ◽  
Regine Kraft ◽  
Katherine Ferrell ◽  
Dawadschargal Bech‐Otschir ◽  
Renate Dumdey ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Complex ◽  
26S Proteasome ◽  
Proteasome Subunits ◽  
Novel Protein

scholarly journals B-1 cell: the precursor of a novel mononuclear phagocyte with immuno-regulatory properties

2009 ◽  
Vol 81 (3) ◽  
pp. 489-496 ◽  
Author(s):  
José Daniel Lopes ◽  
Mario Mariano
Keyword(s):  
Mammalian Cells ◽  
Giant Cells ◽  
Mononuclear Phagocyte ◽  
Different Types ◽  
Series Of Experiments ◽  
B1 Cells ◽  
Regulatory Properties

Characterization of the origin, properties, functions and fate of cells is a fundamental task for the understanding of physiological and pathological phenomena. Despite the bulk of knowledge concerning the diverse characteristics of mammalian cells, some of them, such as B-1 cells, are still poorly understood. Here we report the results obtained in our laboratory on these cells in the last 10 years. After showing that B-1 cells could be cultured and amplified in vitro, a series of experiments were performed with these cells. They showed that B1 cells reside mostly in the peritoneal and pleural cavities, migrate to distant inflammatory foci, coalesce to form giant cells and participate in granuloma formation, both in vitro and in vivo. They are also able to present antigens to immunologically responsive cells and are endowed with regulatory properties. Further, we have also shown that these cells facilitate different types of infection as well as tumor growth and spreading. These data are presently reviewed pointing to a pivotal role that these cells may play in innate and acquired immunity.

scholarly journals Dissection of acute stimulus-inducible nucleosome remodeling in mammalian cells

2019 ◽  
Author(s):  
Federico Comoglio ◽  
Marta Simonatto ◽  
Sara Polletti ◽  
Xin Liu ◽  
Stephen T. Smale ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Regulatory Elements ◽  
Micrococcal Nuclease ◽  
Nucleosome Remodeling ◽  
Nucleosome Dynamics ◽  
Nucleosome Organization ◽  
Regulatory Information ◽  
Different Types ◽  
Genomic Regions ◽  
The Impact

ABSTRACTAccessibility of the genomic regulatory information is largely controlled by the nucleosome-organizing activity of transcription factors (TFs). Whereas stimulus-induced TFs bind to genomic regions that are maintained accessible by lineage-determining TFs, they also increase accessibility of thousands of cis-regulatory elements. Nucleosome remodeling events underlying such changes and their interplay with basal positioning are unknown. Here, we devised a novel quantitative framework discriminating different types of nucleosome remodeling events in micrococcal nuclease ChIP-seq datasets and used it to analyze nucleosome dynamics at stimulus-regulated cis-regulatory elements. At enhancers, remodeling preferentially affected poorly positioned nucleosomes while sparing well-positioned nucleosomes flanking the enhancer core, indicating that inducible TFs do not suffice to overrule basal nucleosomal organization maintained by lineage-determining TFs. Remodeling events appeared to be combinatorially driven by multiple TFs, with distinct TFs showing however different remodeling efficiencies. Overall, these data provide a systematic view of the impact of stimulation on nucleosome organization and genome accessibility in mammalian cells.

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 IFNγ Modulates the Immunopeptidome of Triple Negative Breast Cancer Cells by Enhancing and Diversifying Antigen Processing and Presentation

2021 ◽  
Vol 12 ◽  
Author(s):  
Gabriel Goncalves ◽  
Kerry A. Mullan ◽  
Divya Duscharla ◽  
Rochelle Ayala ◽  
Nathan P. Croft ◽  
...  
Keyword(s):  
Breast Cancer ◽  
T Cell ◽  
Triple Negative Breast Cancer ◽  
Antigen Processing ◽  
Triple Negative ◽  
High Resolution Mass Spectrometry ◽  
Human Leukocyte ◽  
Interferon Γ ◽  
Inflammatory Conditions ◽  
Viable Approach

Peptide vaccination remains a viable approach to induce T-cell mediated killing of tumors. To identify potential T-cell targets for Triple-Negative Breast Cancer (TNBC) vaccination, we examined the effect of the pro-inflammatory cytokine interferon-γ (IFNγ) on the transcriptome, proteome, and immunopeptidome of the TNBC cell line MDA-MB-231. Using high resolution mass spectrometry, we identified a total of 84,131 peptides from 9,647 source proteins presented by human leukocyte antigen (HLA)-I and HLA-II alleles. Treatment with IFNγ resulted in a remarkable remolding of the immunopeptidome, with only a 34% overlap between untreated and treated cells across the HLA-I immunopeptidome, and expression of HLA-II only detected on treated cells. IFNγ increased the overall number, diversity, and abundance of peptides contained within the immunopeptidome, as well increasing the coverage of individual source antigens. The suite of peptides displayed under conditions of IFNγ treatment included many known tumor associated antigens, with the HLA-II repertoire sampling 17 breast cancer associated antigens absent from those sampled by HLA-I molecules. Quantitative analysis of the transcriptome (10,248 transcripts) and proteome (6,783 proteins) of these cells revealed 229 common proteins and transcripts that were differentially expressed. Most of these represented downstream targets of IFNγ signaling including components of the antigen processing machinery such as tapasin and HLA molecules. However, these changes in protein expression did not explain the dramatic modulation of the immunopeptidome following IFNγ treatment. These results demonstrate the high degree of plasticity in the immunopeptidome of TNBC cells following cytokine stimulation and provide evidence that under pro-inflammatory conditions a greater variety of potential HLA-I and HLA-II vaccine targets are unveiled to the immune system. This has important implications for the development of personalized cancer vaccination strategies.

Sign in / Sign up

Export Citation Format

Share Document