scholarly journals Unique Protein Interaction Networks Define The Chromatin Remodeling Module of The NuRD Complex

2021 ◽  
Author(s):  
Mehdi Sharifi Tabar ◽  
Caroline Giardina ◽  
Yue Julie Feng ◽  
Habib Francis ◽  
Hakimeh Moghaddas Sani ◽  
...  

AbstractThe combination of four proteins and their paralogues including MBD2/3, GATAD2A/B, CDK2AP1, and CHD3/4/5, which we refer to as the MGCC module, form the chromatin remodeling module of the Nucleosome Remodeling and Deacetylase (NuRD) complex, a gene repressor complex. Specific paralogues of the MGCC subunits such as MBD2 and CHD4 are amongst the key repressors of adult-stage fetal globin and provide important targets for molecular therapies in beta (β)-thalassemia. However, mechanisms by which the MGCC module acquires paralogue-specific function and specificity have not been addressed to date. Understanding the protein-protein interaction (PPI) network of the MGCC subunits is essential in defining underlying mechanisms and developing treatment strategies. Therefore, using pulldown followed by mass spectrometry analysis (PD-MS) we report a proteome-wide interaction network of the MGCC module in a paralogue-specific manner. Our data also demonstrate that the disordered C-terminal region of CHD3/4/5 is a gateway to incorporate remodeling activity into both the ChAHP (CHD4, ADNP, HP1γ) and NuRD complexes in a mutually exclusive manner. We define a short aggregation prone region (APR) within the C-terminal segment of GATAD2B that is essential for the interaction of CHD4 and CDK2AP1 with the NuRD complex. Finally, we also report an association of CDK2AP1 with the Nuclear Receptor Co-Repressor (NCOR) complex. Overall, this study provides insight into the possible mechanisms through which the MGCC module can achieve specificity and diverse biological functions.

2021 ◽  
Author(s):  
Hongwei Chu ◽  
Changqing Wu ◽  
Qun Zhao ◽  
Rui Sun ◽  
Kuo Yang ◽  
...  

Abstract Sorafenib is commonly used to treat advanced human hepatocellular carcinoma (HCC). However, clinical efficacy has been limited by drug resistance. In this study, we used label-free quantitative proteomic analysis to systematically investigate the underlying mechanisms of sorafenib resistance in HCC cells. A total of 1709 proteins were confidently quantified. Among them, 89 were differentially expressed, and highly enriched in the processes of cell-cell adhesion, negative regulation of apoptosis, response to drug and metabolic processes involving in sorafenib resistance. Notably, folate receptor α (FOLR1) was found to be significantly upregulated in resistant HCC cells. In addition, in-vitro studies showed that overexpression of FOLR1 decreased the sensitivity of HCC cells to sorafenib, whereas siRNA-directed knockdown of FOLR1 increased the sensitivity of HCC cells to sorafenib. Immunoprecipitation-mass spectrometry analysis suggested a strong link between FOLR1 and autophagy related proteins. Further biological experiments found that FOLR1-related sorafenib resistance was accompanied by the activation of autophagy, whereas inhibition of autophagy significantly reduced FOLR1-induced cell resistance. These results suggest the driving role of FOLR1 in HCC resistance to sorafenib, which may be exerted through FOLR1-induced autophagy. Therefore, this study may provide new insights into understanding the mechanism of sorafenib resistance.


2017 ◽  
Vol 114 (28) ◽  
pp. 7408-7413 ◽  
Author(s):  
Yan Jin ◽  
Yaohui Chen ◽  
Shimin Zhao ◽  
Kun-Liang Guan ◽  
Yuan Zhuang ◽  
...  

The involvement of host factors is critical to our understanding of underlying mechanisms of transposition and the applications of transposon-based technologies. Modified piggyBac (PB) is one of the most potent transposon systems in mammals. However, varying transposition efficiencies of PB among different cell lines have restricted its application. We discovered that the DNA–PK complex facilitates PB transposition by binding to PB transposase (PBase) and promoting paired-end complex formation. Mass spectrometry analysis and coimmunoprecipitation revealed physical interaction between PBase and the DNA–PK components Ku70, Ku80, and DNA-PKcs. Overexpression or knockdown of DNA–PK components enhances or suppresses PB transposition in tissue culture cells, respectively. Furthermore, germ-line transposition efficiency of PB is significantly reduced in Ku80 heterozygous mutant mice, confirming the role of DNA–PK in facilitating PB transposition in vivo. Fused dimer PBase can efficiently promote transposition. FRET experiments with tagged dimer PBase molecules indicated that DNA–PK promotes the paired-end complex formation of the PB transposon. These data provide a mechanistic explanation for the role of DNA–PK in facilitating PB transposition and suggest a transposition-promoting manipulation by enhancing the interaction of the PB ends. Consistent with this, deletions shortening the distance between the two PB ends, such as PB vectors with closer ends (PB-CE vectors), have a profound effect on transposition efficiency. Taken together, our study indicates that in addition to regulating DNA repair fidelity during transposition, DNA–PK also affects transposition efficiency by promoting paired-end complex formation. The approach of CE vectors provides a simple practical solution for designing efficient transposon vectors.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Baoman Wang ◽  
Fei Yuan ◽  
Xiangyin Kong ◽  
Lan-Dian Hu ◽  
Yu-Dong Cai

Apoptosis is the process of programmed cell death (PCD) that occurs in multicellular organisms. This process of normal cell death is required to maintain the balance of homeostasis. In addition, some diseases, such as obesity, cancer, and neurodegenerative diseases, can be cured through apoptosis, which produces few side effects. An effective comprehension of the mechanisms underlying apoptosis will be helpful to prevent and treat some diseases. The identification of genes related to apoptosis is essential to uncover its underlying mechanisms. In this study, a computational method was proposed to identify novel candidate genes related to apoptosis. First, protein-protein interaction information was used to construct a weighted graph. Second, a shortest path algorithm was applied to the graph to search for new candidate genes. Finally, the obtained genes were filtered by a permutation test. As a result, 26 genes were obtained, and we discuss their likelihood of being novel apoptosis-related genes by collecting evidence from published literature.


2019 ◽  
Author(s):  
Rodrigo O. de Castro ◽  
Victor Goitea ◽  
Luciana Previato ◽  
Agustin Carbajal ◽  
Courtney T. Griffin ◽  
...  

AbstractTestis development and sustained germ cell production in adults rely on the establishment of spermatogonia stem cells and their proper differentiation into mature gametes. Control of these processes involves not only promoting the expression of genes required for cell survival and differentiation but also repressing other cell fates. This level of transcriptional control requires chromatin-remodeling complexes that restrict or promote transcription machinery. Here, we investigated the roles of the NUcleosome Remodeling and Deacetylase (NURD) complex during spermatogenesis. Our cellular and biochemical analyses revealed differential expression and composition of NURD subunits in gametocytes at different stages of testis development. Germ cell-specific deletion of the NURD catalytic component CHD4, but not CHD3, resulted in arrested early gamete development due to failed cell survival of the undifferentiated spermatogonia stem cell population. Genome-wide CHD4 chromatin localization and transcriptomic analyses revealed that CHD4 binds the promoters and regulates the expression of genes involved in spermatogonia cell survival and differentiation. These results uncover the requirements of CHD4 in mammalian gonad development, and point to unique roles for the NURD complex with respect to other chromatin remodelers during gamete development.Significance StatementGametogenesis is a fundamental developmental program required for sustained fertility and survival of all sexually reproducing species. The developing male gamete undergoes numerous cell divisions and developmental stage transitions that are carefully monitored by epigenetic mechanisms. One prominent mechanism is directed by chromatin remodeling complexes, which modify chromatin structure and thereby control fundamental cellular processes such as gene transcription. In this work, we focused in understanding the role of CHD4 and CHD3 proteins, catalytic subunits of the NURD chromatin-remodeling complex, in mouse gametogenesis. We find that CHD4 has an essential function in gametogenesis, with an absolute requirement for survival of spermatogonia populations in the developing testis. This is accompanied by CHD4-mediated transcriptional regulation of genes important for spermatogonia survival, and differentiation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongfei Xu ◽  
Zhen Wang ◽  
Miao Chen ◽  
Wenting Zhao ◽  
Tingting Tao ◽  
...  

Abstract Background Pathological cardiac hypertrophy is a major contributor of heart failure (HF), which seriously threatens human’s health world widely. Deregulation of m6A RNA methylation, and m6A methyltransferases and de-methyltransferases have been demonstrated to act essential roles in cardiac hypertrophy and HF. Here, we studied the potential roles and its underlying mechanisms of m6A Reader YTHDF proteins in HF. In this study, we constructed HF mouse model by transverse aortic constriction surgery. Primary cardiomyocytes were isolated and stimulated with isoproterenol (ISO) or phenylephrine (PHE) to induce myocardial hypertrophy. Results Through single-cell RNA-seq analysis, immunofluorescent staining, HE staining, Western blotting, and real time-PCR detections, we found that YTHDF2 mRNA and protein level, but not YTHDF1 or YTHDF3, was significantly increased during HF development. YTHDF2 overexpression could efficiently alleviate cardiac hypertrophy. Furthermore, through immunoprecipitation accompanied with mass spectrometry analysis, Gene Ontology (GO) analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, we found that ISO stimulation did not evidently affect YTHDF2-interacting proteins. However, ISO or PHE stimulation significantly increased YTHDF2 protein interacting with Myh7 (beta-myosin heavy chain) mRNA, an important cardiac hypertrophy marker, in an m6A-dependent manner. Knockdown of Myh7 or deletion of the YTH domain of YTHDF2 reversed the protective effects of YTHDF2 on cardiac hypertrophy. Finally, we found that ISO or PHE stimulation promoted YTHDF2 protein expression through enhancing Ythdf2 mRNA stability in an m6A-dependent manner in cardiomyocytes. Conclusions Overall, our results indicate that the m6A Reader YTHDF2 suppresses cardiac hypertrophy via Myh7 mRNA decoy in an m6A-dependent manner. This study highlights the functional importance of YTHDF2-dependent cardiac m6A mRNA regulation during cardiac hypertrophy, and provides a novel mechanistic insight into the therapeutic mechanisms of YTHDF2.


FEBS Journal ◽  
2021 ◽  
Author(s):  
Mehdi Sharifi Tabar ◽  
Caroline Giardina ◽  
Yue Feng ◽  
Habib Francis ◽  
Hakimeh Moghaddas sani ◽  
...  

2020 ◽  
Author(s):  
Heesun Kim ◽  
Yue-He Ding ◽  
Gangming Zhang ◽  
Yong-Hong Yan ◽  
Darryl Conte ◽  
...  

SUMMARYEukaryotic cells use guided search to coordinately control dispersed genetic elements. The transitive effectors of these mechanisms, Argonaute proteins and their small-RNA co-factors, engage nascent RNAs and chromatin-associated proteins to direct transcriptional silencing. The small ubiquitin-like modifier (SUMO) has been shown to promote the induction and maintenance of silent chromatin (called heterochromatin) in yeast, plants, and animals. Here we show that Argonaute-directed transcriptional silencing in C. elegans requires SUMOylation of the type 1 histone deacetylase HDA-1. SUMOylation of HDA-1 promotes interactions with components of the nucleosome remodeling and deacetylase (NuRD) complex and with the nuclear Argonaute HRDE-1/WAGO-9. Our findings suggest how HDAC1 SUMOylation promotes the association of HDAC and other chromatin remodeling factors with a nuclear Argonaute in order to initiate de novo heterochromatin silencing.


2020 ◽  
Author(s):  
Natan Nagar ◽  
Noa Ecker ◽  
Gil Loewenthal ◽  
Oren Avram ◽  
Daniella Ben-Meir ◽  
...  

AbstractDegradation of intracellular proteins in Gram-negative bacteria regulates various cellular processes and serves as a quality control mechanism by eliminating damaged proteins. To understand what causes the proteolytic machinery of the cell to degrade some proteins while sparing others, we employed a quantitative pulsed-SILAC (Stable Isotope Labeling with Amino acids in Cell culture) method followed by mass spectrometry analysis to determine the half-lives for the proteome of exponentially growing Escherichia coli, under standard conditions. We developed a likelihood-based statistical test to find actively degraded proteins, and identified dozens of novel proteins that are fast-degrading. Finally, we used structural, physicochemical and protein-protein interaction network descriptors to train a machine-learning classifier to discriminate fast-degrading proteins from the rest of the proteome. Our combined computational-experimental approach provides means for proteomic-based discovery of fast degrading proteins in bacteria and the elucidation of the factors determining protein half-lives and have implications for protein engineering. Moreover, as rapidly degraded proteins may play an important role in pathogenesis, our findings could identify new potential antibacterial drug targets.


2021 ◽  
Author(s):  
Lauren Alicia Agro

The FLT3-FLT3L receptor complex is responsible for the proliferation and differentiation of hematopoietic progenitor and stem cells, and is involved in several hematological malignancies. A truncated, soluble form of FLT3L was amplified from the full-length sequence by PCR and cloned into a genomic integration and expression vector for Kluyveromyces lactis. Expression and secretion of the 161 amino acid FLT3L was analyzed by SDS-PAGE and Western blot and showed smeared bands around 50kDa consistent with a high level of varying glycosylation as expected. A yield of 100ug/mL of culture was obtained. Purification was performed by Ni-affinity chromatography and the protein was confirmed to be in the elution fraction via mass spectrometry analysis. Purified FLT3L was able to activate RAW264.7 cells after 24hr incubation period causing large vacuoles and a dendritic appearance. FLT3L will be utilized for LARC protein interaction studies to search for interactors that might serve as therapeutic agents in human body fluids and cell culture models of myeloid leukemia.


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