scholarly journals Mitochondrial proteomic approach reveals galectin-7 as a novel BCL-2 binding protein in human cells

2011 ◽  
Vol 22 (7) ◽  
pp. 999-1013 ◽  
Author(s):  
Christelle Villeneuve ◽  
Laurent Baricault ◽  
Ludovic Canelle ◽  
Nadia Barboule ◽  
Carine Racca ◽  
...  

Although the anti-apoptotic activity of Bcl-2 has been extensively studied, its mode of action remains incompletely understood. Deciphering the network of Bcl-2 interacting factors is necessary to better understand the key function of Bcl-2 in apoptosis initiation. To identify novel Bcl-2 mitochondrial partners, we have combined a Bcl-2 immunocapture with a mass spectrometry analysis using highly pure mitochondrial fractions isolated from human cancer cells. We identified at high confidence 127 potential Bcl-2–interacting proteins. Gene ontology mining reveals enrichment for mitochondrial proteins, endoplasmic reticulum–associated proteins, and cytoskeleton-associated proteins. Importantly, we report the identification of galectin-7 (Gal7), a member of a family of β-galactoside–binding lectins that was already known to exhibit a pro-apoptotic function, as a new mitochondrial Bcl-2 interacting partner. Our data further show that endogenous Bcl-2 coimmunoprecipitates with Gal7 and that recombinant Gal7 directly interacts with recombinant Bcl-2. A fraction of Gal7 is constitutively localized at mitochondria in a Bcl-2–dependent manner and sensitizes the mitochondria to the apoptotic signal. In addition, we show that the Bcl-2/Gal7 interaction is abolished following genotoxic stress. Taken together, our findings suggest that the binding of Gal7 to Bcl-2 may constitute a new target for enhancing the intrinsic apoptosis pathway.

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1209 ◽  
Author(s):  
Liwei Ma ◽  
Haijun Wang ◽  
Jing Wang ◽  
Lei Liu ◽  
Song Zhang ◽  
...  

A series of novel steroidal 5α,8α-endoperoxide derivatives bearing semicarbazone (7a–g) or thiosemicarbazone (7h–k) side chain were designed, synthesized and evaluated for their cytotoxicities in four human cancer cell lines (HepG2, HCT-116, MCF-7, and A549) using the MTT assay in vitro. The results showed that compound 7j exhibited significant cytotoxic activity against HepG2 cells (IC50 = 3.52 μM), being more potent than ergosterol peroxide. Further cellular mechanism studies in HepG2 cells indicated that compound 7j triggered the mitochondrial-mediated apoptosis by decreasing mitochondrial membrane potential (MMP), which was associated with up-regulation of Bax, down-regulation of Bcl-2, activation levels of the caspase cascade, and formation of reactive oxygen species (ROS). The above findings indicated that compound 7j may be used as a promising skeleton for antitumor agents with improved efficacy.


2020 ◽  
Vol 21 (19) ◽  
pp. 7415
Author(s):  
Hicham Benabdelkamel ◽  
Hanadi Alamri ◽  
Meshail Okla ◽  
Afshan Masood ◽  
Mai Abdel Jabar ◽  
...  

Cystic fibrosis (CF), the most common lethal autosomal recessive disorder among Caucasians, is caused by mutations in the CF transmembrane conductance regulator (CFTR) chloride channel gene. Despite significant advances in the management of CF patients, novel disease-related biomarkers and therapies must be identified. We performed serum proteomics profiling in CF patients (n = 28) and healthy subjects (n = 10) using the 2D-DIGE MALDI-TOF proteomic approach. Out of a total of 198 proteins identified, 134 showed a statistically significant difference in abundance and a 1.5-fold change (ANOVA, p < 0.05), including 80 proteins with increased abundance and 54 proteins with decreased abundance in CF patients. A multiple reaction monitoring-mass spectrometry analysis of six differentially expressed proteins identified by a proteomic approach (DIGE-MALD-MS) showed a significant increase in C3 and CP proteins and a decrease in APOA1, Complement C1, Hp, and RBP4proteins compared with healthy controls. Fifteen proteins were identified as potential biomarkers for CF diagnosis. An ingenuity pathway analysis of the differentially regulated proteins indicates that the central nodes dysregulated in CF subjects involve pro-inflammatory cytokines, ERK1/2, and P38 MAPK, which are primarily involved in catalytic activities and metabolic processes. The involved canonical pathways include those related to FXR/RXR, LXR/RXR, acute phase response, IL12, nitric oxide, and reactive oxygen species in macrophages. Our data support the current efforts toward augmenting protease inhibitors in patients with CF. Perturbations in lipid and vitamin metabolism frequently observed in CF patients may be partly due to abnormalities in their transport mechanism.


2020 ◽  
pp. 108201322092914
Author(s):  
Enrique Sentandreu ◽  
Claudia Fuente-García ◽  
José L Navarro ◽  
Miguel A Sentandreu

Bovine sarcoplasmic sub-proteome was studied through a straightforward gel-free pipeline supported by liquid isoelectric focusing (OFFGEL) protein fractionation coupled to liquid chromatography-mass spectrometry (LC-MS) analysis. Full-MS and data-dependent MS/MS analyses were simultaneously performed by a conventional three-dimensional ion-trap addressing targeted quantitative and untargeted qualitative research, respectively. There were unambiguously identified 47 proteins distributed along 12 OFFGEL fractions assayed. Regarding intermediate- and high-abundant peptides, bulky quantitative data processing performed by MZmine 2 freeware yielded a satisfactory linearity and coefficient of variation with r2 in the 0.95–0.99 range and about 25%, respectively. Up to 41 peptides from 20 identified proteins were relatively quantified throughout OFFGEL fractions. This reliable, flexible and affordable gel-free proteomic approach could be readily implemented by industry to improve quality assessment of protein-based food products.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Christopher Platen ◽  
Stephan Dreschers ◽  
Jessica Wappler ◽  
Andreas Ludwig ◽  
Stefan Düsterhöft ◽  
...  

Neonates are extremely susceptible to bacterial infections, and evidences suggest that phagocytosis-induced cell death (PICD) is less frequently triggered in neonatal monocytes than in monocytes from adult donors. An insufficient termination of the inflammatory response, leading to a prolonged survival of neonatal monocytes with ongoing proinflammatory cytokine release, could be associated with the progression of various inflammatory diseases in neonates. Our previous data indicate that amphiregulin (AREG) is increasingly expressed on the cell surface of neonatal monocytes, resulting in remarkably higher soluble AREG levels after proteolytic shedding. In this study, we found that E. coli-infected neonatal monocytes show an increased phosphorylation of ERK, increased expression of Bcl-2 and Bcl-XL, and reduced levels of cleaved caspase-3 and caspase-9 compared to adult monocytes. In both cell types, additional stimulation with soluble AREG further increased ERK activation and expression of Bcl-2 and Bcl-XL and reduced levels of cleaved caspase-3 and caspase-9 in an EGFR-dependent manner. These data suggest that reduced PICD of neonatal monocytes could be due to reduced intrinsic apoptosis and that AREG can promote protection against PICD. This reduction of the intrinsic apoptosis pathway in neonatal monocytes could be relevant for severely prolonged inflammatory responses of neonates.


2009 ◽  
Vol 191 (14) ◽  
pp. 4647-4655 ◽  
Author(s):  
Rozenn Gardan ◽  
Colette Besset ◽  
Alain Guillot ◽  
Christophe Gitton ◽  
Véronique Monnet

ABSTRACT In gram-positive bacteria, oligopeptide transport systems, called Opp or Ami, play a role in nutrition but are also involved in the internalization of signaling peptides that take part in the functioning of quorum-sensing pathways. Our objective was to reveal functions that are controlled by Ami via quorum-sensing mechanisms in Streptococcus thermophilus, a nonpathogenic bacterium widely used in dairy technology in association with other bacteria. Using a label-free proteomic approach combining one-dimensional electrophoresis with liquid chromatography-tandem mass spectrometry analysis, we compared the proteome of the S. thermophilus LMD-9 to that of a mutant deleted for the subunits C, D, and E of the ami operon. Both strains were grown in a chemically defined medium (CDM) without peptides. We focused our attention on proteins that were no more detected in the ami deletion mutant. In addition to the three subunits of the Ami transporter, 17 proteins fulfilled this criterion and, among them, 7 were similar to proteins that have been identified as essential for transformation in S. pneumoniae. These results led us to find a condition of growth, the early exponential state in CDM, that allows natural transformation in S. thermophilus LMD-9 to turn on spontaneously. Cells were not competent in M17 rich medium. Furthermore, we demonstrated that the Ami transporter controls the triggering of the competence state through the control of the transcription of comX, itself controlling the transcription of late competence genes. We also showed that one of the two oligopeptide-binding proteins of strain LMD-9 plays the predominant role in the control of competence.


2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Euan J. Rodger ◽  
Carolyn M. Porteous ◽  
Gregory T. Jones ◽  
Michael Legge ◽  
Torsten Kleffmann ◽  
...  

Background. Mouse models of hypercholesterolaemia have been used to identify arterial proteins involved in atherosclerosis. As the liver is extremely sensitive to dyslipidemia, one might expect major changes in the abundance of liver proteins in these models even before atherosclerosis develops. Methods. Lipid levels were measured and a proteomic approach was used to quantify proteins in the livers of mice with an elevated low-density lipoprotein (LDL) and the presence of lipoprotein(a) [Lp(a)] but no atherosclerosis. Results. The livers of Lp(a) mice showed an increased triglyceride but reduced phospholipid and oxidised lipid content. Two-dimensional gel electrophoresis and mass spectrometry analysis identified 24 liver proteins with significantly increased abundance in Lp(a) mice (P<0.05). A bioinformatic analysis of the 24 proteins showed the major effect was that of an enhanced antioxidant and lipid efflux response with significant increases in antioxidant (Park7, Gpx1, Prdx6, and Sod1) and lipid metabolism proteins (Fabp4, Acaa2, apoA4, and ApoA1). Interestingly, human liver cells treated with Lp(a) showed significant increases in Gpx1 and Prdx6 but not Sod1 or Park7. Conclusions. The presence of human LDL and Lp(a) in mice promotes an enhanced flux of lipids into the liver which elicits an antioxidant and lipid export response before the onset of atherosclerosis. The antioxidant response can be reproduced in human liver cells treated with Lp(a).


Pharmacology ◽  
2019 ◽  
Vol 105 (3-4) ◽  
pp. 164-172
Author(s):  
Shuangbo Fan ◽  
Qian Xu ◽  
Liang Wang ◽  
Yulin Wan ◽  
Sheng Qiu

SMBA1 (small-molecule Bax agonists 1), a small molecular activator of Bax, is a potential anti-tumour agent. In the present study, we investigated the biological effects of SMBA1 on glioblastoma (GBM) cells. SMBA1 reduced the viabilities of U87MG, U251 and T98G cells in a time- and dose-dependent manner. Moreover, treatment with SMBA1 induced cell cycle arrest at the G2/M phase transition, accompanied by the downregulation of Cdc25c and cyclin B1 and the upregulation of p21. SMBA1 also induced apoptosis of GBM cells in a dose-dependent manner. Mechanistically, SMBA1 induced apoptosis via the intrinsic pathway. Silencing of Bax or ectopic expression of Bcl-2 significantly inhibited SMBA1-induced apoptosis. Moreover, SMBA1 inhibited the growth of U87MG xenograft tumours in vivo. Overall, SMBA1 shows anti-proliferative effects against GBM cells through activation of the intrinsic apoptosis pathway.


2002 ◽  
Vol 70 (1) ◽  
pp. 368-379 ◽  
Author(s):  
Silvia Montigiani ◽  
Fabiana Falugi ◽  
Maria Scarselli ◽  
Oretta Finco ◽  
Roberto Petracca ◽  
...  

ABSTRACT Chlamydia pneumoniae, a human pathogen causing respiratory infections and probably contributing to the development of atherosclerosis and heart disease, is an obligate intracellular parasite which for replication needs to productively interact with and enter human cells. Because of the intrinsic difficulty in working with C. pneumoniae and in the absence of reliable tools for its genetic manipulation, the molecular definition of the chlamydial cell surface is still limited, thus leaving the mechanisms of chlamydial entry largely unknown. In an effort to define the surface protein organization of C. pneumoniae, we have adopted a combined genomic-proteomic approach based on (i) in silico prediction from the available genome sequences of peripherally located proteins, (ii) heterologous expression and purification of selected proteins, (iii) production of mouse immune sera against the recombinant proteins to be used in Western blotting and fluorescence-activated cell sorter (FACS) analyses for the identification of surface antigens, and (iv) mass spectrometry analysis of two-dimensional electrophoresis (2DE) maps of chlamydial protein extracts to confirm the presence of the FACS-positive antigens in the chlamydial cell. Of the 53 FACS-positive sera, 41 recognized a protein species with the expected size on Western blots, and 28 of the 53 antigens shown to be surface-exposed by FACS were identified on 2DE maps of elementary-body extracts. This work represents the first systematic attempt to define surface protein organization in C. pneumoniae.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2443-2443
Author(s):  
Xinyang Zhao ◽  
Li Zhang ◽  
Rui Wang ◽  
Ngoc Tung Trans ◽  
Hairui Su ◽  
...  

Abstract More than 90% of under one year old infants with acute megakaryoblastic leukemia (AMKL) have chromosome translocation t(1;22)(p13;q13) with RBM15 fused to MKL1. RBM15 encodes an RNA binding protein important for hematopoietic stem cell self-renewal and differentiation. In agreement with its roles in AMKL, RBM15 is required for normal megakaryocyte differentiation. We found that higher expression of PRMT1 (Protein Arginine Methyltransferase) is commonly seen in M7 leukemia patient samples than other types of myeloid leukemia and that RBM15 is a bona fide methylation target for PRMT1. Using mass spectrometry analysis, we mapped the PRMT1 mediated mono-methylated site. The enzymatic activity of the PRMT1 V2 isoform is required for RBM15 degradation, as both shRNA molecules knocking down PRMT1 and small chemical PRMT1 inhibitors stabilize the RBM15 protein. Mutation of the methylation site to lysine blocks the ubiquitylation mediated degradation. Thus the degradation is a methylation dependent process. We identified the E3 ligase responsible for the degradation. Down-regulation of the RBM15 protein changes the isoform ratio of genes including GATA1 critical megakaryocyte differentiation. We found that RBM15 regulates its interaction with SF3B1A in methylation dependent manner during alternative splicing of GATA1 pre-mRNA. Thus, via methylation triggered RBM15 degradation, the megakaryocyte progenitor cells maintain a delicate balance between differentiation and proliferation by keeping the proper ratio of GATA1s and GATA1-full length mRNA. SF3B1A has been shown to be mutated in myeloid dysplasia syndrome and in several different types of leukemia. Methylation by PRMT1 links the two types of leukemic genes into a single pathway. Our results imply that targeting PRMT1/RBM15 pathway might be a potential therapy for AMKL and other blood malignancies. Disclosures: No relevant conflicts of interest to declare.


2021 ◽  
Vol 14 ◽  
Author(s):  
Marie Pronot ◽  
Félicie Kieffer ◽  
Anne-Sophie Gay ◽  
Delphine Debayle ◽  
Raphaël Forquet ◽  
...  

Synapses are highly specialized structures that interconnect neurons to form functional networks dedicated to neuronal communication. During brain development, synapses undergo activity-dependent rearrangements leading to both structural and functional changes. Many molecular processes are involved in this regulation, including post-translational modifications by the Small Ubiquitin-like MOdifier SUMO. To get a wider view of the panel of endogenous synaptic SUMO-modified proteins in the mammalian brain, we combined subcellular fractionation of rat brains at the post-natal day 14 with denaturing immunoprecipitation using SUMO2/3 antibodies and tandem mass spectrometry analysis. Our screening identified 803 candidate SUMO2/3 targets, which represents about 18% of the synaptic proteome. Our dataset includes neurotransmitter receptors, transporters, adhesion molecules, scaffolding proteins as well as vesicular trafficking and cytoskeleton-associated proteins, defining SUMO2/3 as a central regulator of the synaptic organization and function.


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