Dataset Information

Quantitative membrane proteomics reveals new cellular targets of viral immune modulators.

ABSTRACT: Immunomodulators of pathogens frequently affect multiple cellular targets, thus preventing recognition by different immune cells. For instance, the K5 modulator of immune recognition (MIR2) from Kaposi sarcoma-associated herpesvirus prevents activation of cytotoxic T cells, natural killer cells, and natural killer T cells by downregulating major histocompatibility complex (MHC) class I molecules, the MHC-like molecule CD1, the cell adhesion molecules ICAM-1 and PECAM, and the co-stimulatory molecule B7.2. K5 belongs to a family of viral- and cellular-membrane-spanning RING ubiquitin ligases. While a limited number of transmembrane proteins have been shown to be targeted for degradation by this family, it is unknown whether additional targets exist. We now describe a quantitative proteomics approach to identify novel targets of this protein family. Using stable isotope labeling by amino acids, we compared the proteome of plasma, Golgi, and endoplasmic reticulum membranes in the presence and absence of K5. Mass spectrometric protein identification revealed four proteins that were consistently underrepresented in the plasma membrane of K5 expression cells: MHC I (as expected), bone marrow stromal antigen 2 (BST-2, CD316), activated leukocyte cell adhesion molecule (ALCAM, CD166) and Syntaxin-4. Downregulation of each of these proteins was independently confirmed by immunoblotting with specific antibodies. We further demonstrate that ALCAM is a bona fide target of both K5 and the myxomavirus homolog M153R. Upon exiting the endoplasmic reticulum, ALCAM is ubiquitinated in the presence of wild-type, but not RING-deficient or acidic motif-deficient, K5, and is targeted for lysosomal degradation via the multivesicular body pathway. Since ALCAM is the ligand for CD6, a member of the immunological synapse of T cells, its removal by viral immune modulators implies a role for CD6 in the recognition of pathogens by T cells. The unbiased global proteome analysis therefore revealed novel immunomodulatory functions of pathogen proteins.

SUBMITTER: Bartee E

PROVIDER: S-EPMC1626102 | biostudies-literature | 2006 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Quantitative membrane proteomics reveals new cellular targets of viral immune modulators.

Bartee Eric E McCormack Ashley A Früh Klaus K

PLoS pathogens 20061001 10

Immunomodulators of pathogens frequently affect multiple cellular targets, thus preventing recognition by different immune cells. For instance, the K5 modulator of immune recognition (MIR2) from Kaposi sarcoma-associated herpesvirus prevents activation of cytotoxic T cells, natural killer cells, and natural killer T cells by downregulating major histocompatibility complex (MHC) class I molecules, the MHC-like molecule CD1, the cell adhesion molecules ICAM-1 and PECAM, and the co-stimulatory mole ...[more]

PMID: 17238276

Similar Datasets

Project description:Celastrol, a natural substance isolated from plant extracts used in traditional Chinese medicine, has been extensively investigated as a possible drug for treatment of cancer, autoimmune diseases, and protein misfolding disorders. Although studies focusing on celastrol's effects in specific cellular pathways have revealed a considerable number of targets in a diverse array of in vitro models there is an essential need for investigations that can provide a global view of its effects. To assess cellular effects of celastrol and to identify target proteins as biomarkers for monitoring treatment regimes, we performed large-scale quantitative proteomics in cultured human lymphoblastoid cells, a cell type that can be readily prepared from human blood samples. Celastrol substantially modified the proteome composition and 158 of the close to 1800 proteins with robust quantitation showed at least a 1.5 fold change in protein levels. Up-regulated proteins play key roles in cytoprotection with a prominent group involved in quality control and processing of proteins traversing the endoplasmic reticulum. Increased levels of proteins essential for the cellular protection against oxidative stress including heme oxygenase 1, several peroxiredoxins and thioredoxins as well as proteins involved in the control of iron homeostasis were also observed. Specific analysis of the mitochondrial proteome strongly indicated that the mitochondrial association of certain antioxidant defense and apoptosis-regulating proteins increased in cells exposed to celastrol. Analysis of selected mRNA transcripts showed that celastrol activated several different stress response pathways and dose response studies furthermore showed that continuous exposure to sub-micromolar concentrations of celastrol is associated with reduced cellular viability and proliferation. The extensive catalog of regulated proteins presented here identifies numerous cellular effects of celastrol and constitutes a valuable biomarker tool for the development and monitoration of disease treatment strategies.

Project description:Unpredictable influenza pandemics, annual epidemics, and sporadic poultry-to-human avian influenza virus infections with high morbidity and mortality rates dictate a need to develop new antiviral approaches. Targeting cellular pathways and processes is a promising antiviral strategy shown to be effective regardless of viral subtypes or viral evolution of drug-resistant variants. Proteomics-based searches provide a tool to reveal the druggable stages of the virus life cycle and to understand the putative antiviral mode of action of the drug(s). Ribonucleases (RNases) of different origins not only demonstrate antiviral effects that are mediated by the direct RNase action on viral and cellular RNAs but can also exert their impact by signal transduction modulation. To our knowledge, studies of the RNase-affected cell proteome have not yet been performed. To reveal cellular targets and explain the mechanisms underlying the antiviral effect employed by the small extra-cellular ribonuclease of Bacillus pumilus (binase) both in vitro and in vivo, qualitative shotgun and quantitative targeted proteomic analyses of the influenza A virus (IAV) H1N1pdm09-infected A549 cells upon binase treatment were performed. We compared proteomes of mock-treated, binase-treated, virus-infected, and virus-infected binase-treated cells to determine the proteins affected by IAV and/or binase. In general, IAV demonstrated a downregulating strategy towards cellular proteins, while binase had an upregulating effect. With the help of bioinformatics approaches, coregulated cellular protein sets were defined and assigned to their biological function; a possible interconnection with the progression of viral infection was conferred. Most of the proteins downregulated by IAV (e.g., AKR1B1, AKR1C1, CCL5, PFN1, RAN, S100A4, etc.) belong to the processes of cellular metabolism, response to stimulus, biological regulation, and cellular localization. Upregulated proteins upon the binase treatment (e.g., AKR1B10, CAP1, HNRNPA2B1, PFN1, PPIA, YWHAB, etc.) are united by the processes of biological regulation, cellular localization, and immune and metabolic processes. The antiviral activity of binase against IAV was expressed by the inversion of virus-induced proteomic changes, resulting in the inhibition of virus-associated processes, including nuclear ribonucleoprotein export (NCL, NPM1, Nup205, and Bax proteins involved) and cytoskeleton remodeling (RDX, PFN1, and TUBB) induced by IAV at the middle stage of single-cycle infection in A549 cells. Modulation of the immune response could be involved as well. Overall, it seems possible that binase exerts its antiviral effects in multiple ways.

Project description:BackgroundAs a rare pathologic subtype, small cell carcinoma of the cervix (SCCC) is characterized by extensive aggressiveness and resistance to current therapies. To date, our knowledge of SCCC origin and progression is limited and sometimes even controversial. Herein, we explored the whole-protein expression profiles in a panel of SCCC cases, aiming to provide more evidence for the precise diagnosis and targeting therapy.MethodsEighteen SCCC samples and six matched normal cervix tissues were collected from January 2013 to December 2017. Data independent acquisition mass spectrometry (DIA) was performed to discriminate the different proteins (DEPs) associated with SCCC. The expression of CDN2A and SYP in corresponding SCCC tissues was verified using immunohistochemistry. GO and KEGG enrichment analyses were used to identify the key DEPs related to SCCC development and tumor recurrence.ResultsAs a result, 1311 DEPs were identified in SCCC tissues (780 up-regulated and 531 down-regulated). In up-regulated DEPs, both GO analysis and KEGG analysis showed the most enriched were related to DNA replication (including nuclear DNA replication, DNA-dependent DNA replication, and cell cycle DNA replication), indicating the prosperous proliferation in SCCC. As for the down-regulated DEPs, GO analysis showed that the most enriched functions were associated with extracellular matrix collagen-containing extracellular matrix. KEGG analysis revealed that the DEPs were enriched in Complement and coagulation cascades, proteoglycans in cancer, and focal adhesion-related pathways. Down-regulation of these proteins could enhance the mobility of cancer cells and establish a favorable microenvironment for tumor metastasis, which might be accounted for the frequent local and distant metastasis in SCCC. Surprisingly, the blood vessels and circulatory system exhibit a down-regulation in SCCC, which might be partly responsible for its resistance to anti-angiogenic regimens. In the stratification analysis of early-stage tumors, a group of enzymes involved in the cancer metabolism was discriminated in these recurrence cases.ConclusionsUsing quantitative proteomics analysis, we first reported the whole-protein expression profiles in SCCC. Significant alterations were found in proteins associated with the enhancement of DNA replication and cellular motility. Besides the association with mitosis, a unique metabolic feature was detected in cases with tumor recurrence. These findings provided novel targets for disease surveillance and treatments, which warranted further validation in the future.

Dataset Information

Quantitative membrane proteomics reveals new cellular targets of viral immune modulators.

Publications

Quantitative membrane proteomics reveals new cellular targets of viral immune modulators.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets