Proteomics corresponding to structural analysis of model Alzheimers brain
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Eclipse
ORGANISM(S): Rattus Norvegicus (ncbitaxon:10116)
SUBMITTER: 
Mohammad Mazhab-Jafari
PROVIDER: MSV000095931 | MassIVE |
REPOSITORIES: MassIVE
Similar Datasets
Project description:Here we report the cryo-electron microscopy (cryo-EM) structures of SUV420H1 associated with canonical nucleosome core particles (NCPs) or H2AZ containing NCPs. We find that SUV420H1 shows conformational change after bound to a nucleosome and make extensive site-specific contacts with histone and DNA regions, thus enabling H4K20 insertion for catalysis specifically. Through in vivo functional analysis, we validated special residues of SUV420H1 that are critical for its catalytic activity and function in chromatin state regulation.Thus, our study provides molecular insights into the nucleosome-based recognition and histone- methylation mechanisms of SUV420H1.
2023-12-04 | GSE236249 | GEO
Project description:Eukaryotic ribosome biogenesis begins with the co-transcriptional assembly of the 90S pre-ribosome. The ‘U three protein’ (UTP) complexes and snoRNA particles arrange around the nascent pre-ribosomal RNA chaperoning its folding and further maturation. The earliest event in this hierarchical process is the binding of the UTP-A complex to the 5’-end of the pre-ribosomal RNA (5’-ETS). This oligomeric complex predominantly consists of β-propeller and α-solenoidal proteins. Here we present the structure of the Utp4 subunit from the thermophilic fungus Chaetomium thermophilum at 2.15 Å resolution and analyze its function by UV RNA-crosslinking (CRAC) and in context of a recent cryo-EM structure of the 90S pre-ribosome. Utp4 consists of two orthogonal and highly basic β-propellers that perfectly fit the EM-data. The Utp4 structure highlights an unusual Velcro-closure of its C-terminal β-propeller as relevant for protein integrity and Utp8 recognition in the context of the pre-ribosome. We provide a first model of the 5’-ETS RNA from an internally hidden 5’-end up to the region that hybridizes to the 3’-hinge sequence of U3 snoRNA and validate a specific Utp4/5’-ETS interaction by CRAC analysis. Altogether Utp4 is central to the UTP-A complex and organizes the 5’-ETS for further maturation.
2017-06-06 | GSE98331 | GEO
Project description:The nuclear factor Dek is notably enriched within chromatin; nevertheless, the precise binding mechanism of Dek to the nucleosome remains elusive. In this study, we employ cryo-electron microscopy (cryo-EM) to elucidate the high-resolution structure of the Dek-Nucleosome Core Particle (NCP) complex. We identify specific domains responsible for DEK interaction with the histone octamer and DNA within the nucleosome. The veracity of these binding domains is confirmed through a series of meticulous biochemical experiments. Subsequently, cellular experiments reveal that Dek lacking nucleosome-binding capacity exhibits a deficiency in chromatin interaction. Remarkably, this impairment induces a shift towards the primitive endoderm fate in mouse embryonic stem cells, underscoring the pivotal role of Dek in determining cell fate through its nucleosomal interactions.
2023-12-31 | GSE247796 | GEO
Project description:The nuclear factor Dek is notably enriched within chromatin; nevertheless, the precise binding mechanism of Dek to the nucleosome remains elusive. In this study, we employ cryo-electron microscopy (cryo-EM) to elucidate the high-resolution structure of the Dek-Nucleosome Core Particle (NCP) complex. We identify specific domains responsible for DEK interaction with the histone octamer and DNA within the nucleosome. The veracity of these binding domains is confirmed through a series of meticulous biochemical experiments. Subsequently, cellular experiments reveal that Dek lacking nucleosome-binding capacity exhibits a deficiency in chromatin interaction. Remarkably, this impairment induces a shift towards the primitive endoderm fate in mouse embryonic stem cells, underscoring the pivotal role of Dek in determining cell fate through its nucleosomal interactions.
2024-01-15 | GSE253062 | GEO
Project description:Retroviral integration is catalyzed by a tetramer of integrase (IN) assembled on viral DNA ends in a stable complex, known as the intasome. How the intasome interfaces with chromosomal DNA, which exists in the form of nucleosomal arrays, is currently unknown. Here we show that the prototype foamy virus (PFV) intasome is proficient at stable capture of nucleosomes as targets for integration. Single-particle cryo-electron microscopy (EM) reveals a multivalent intasome-nucleosome interface involving both gyres of nucleosomal DNA and one H2A-H2B heterodimer. While the histone octamer remains intact, the DNA is lifted from the surface of the H2A-H2B heterodimer to allow integration at strongly preferred superhelix location (SHL) ±3.5 positions. Amino acid substitutions disrupting these contacts impinge on the ability of the intasome to engage nucleosomes in vitro and redistribute viral integration sites on the genomic scale. Our findings elucidate the molecular basis for nucleosome capture by the viral DNA recombination machinery and the underlying nucleosome plasticity that allows integration. Genomic positions of integration sites of WT and mutant PFV vectors in HT1080 cells were determined using ligation-mediated PCR and next generation sequencing. Integration sites of purified recombinant PFV intasome into deproteinized human genomic DNA were used as a reference dataset.
2015-06-10 | E-GEOD-67730 | biostudies-arrayexpress
Project description:Various stressors such as viral infection lead to the suppression of cap-dependent translation and the activation of the integrated stress response (ISR), since the stress-induced phosphorylated eukaryotic translation initiation factor 2 [eIF2(αP)] tightly binds to eIF2B to prevent it from exchanging guanine nucleotide molecules on its substrate, unphosphorylated eIF2. Sandfly fever Sicilian virus (SFSV) evades this cap-dependent translation suppression through the interaction between its nonstructural protein NSs and host eIF2B. However, its precise mechanism has remained unclear. Here, our cryo-electron microscopy (cryo-EM) analysis revealed that SFSV NSs binds to the α-subunit of eIF2B in a competitive manner with eIF2(αP). Together with SFSV NSs, eIF2B retains nucleotide exchange activity even in the presence of eIF2(αP), in line with the cryo-EM structures of the eIF2B•SFSV NSs•unphosphorylated eIF2 complex. A genome-wide ribosome profiling analysis clarified that SFSV NSs expressed in cultured human cells attenuates the ISR triggered by thapsigargin, an endoplasmic reticulum stress inducer. Furthermore, SFSV NSs introduced in rat hippocampal neurons and human induced-pluripotent stem (iPS) cell-derived motor neurons exhibited neuroprotective effects against the ISR-inducing stress. Since ISR inhibition is beneficial in various neurological disease models, SFSV NSs is promising as a therapeutic ISR inhibitor.
2021-11-11 | GSE174764 | GEO
Project description:N6-methyladenosine (m6A) is the most abundant ribonucleotide modification among the eukaryotic messenger RNAs (mRNAs). The m6A “writer” is composed of an m6A-METTL complex (MAC), the catalytic subunit, and an m6A-METTL associated complex (MACOM), the regulatory subunit essential for the enzymatic activity. Here we report the cryo-electron microscopy (cryo-EM) structures of MACOM at 3.0-Å resolution, uncovering that WTAP and VIRMA form the core structure of MACOM and ZC3H13 stretches the conformation by binding VIRMA. The lower 4.4-Å resolution cryo-EM datamap of MACOM in complex with MAC, in combination with crosslinking mass spectrometry and GST-pulldown analysis, elucidates a plausible model of the m6A writer complex, in which MACOM binds MAC mainly through WTAP and METTL3 interaction and both components directly contact with RNA substrates revealed by 4-thiouridine-labeled RNA crosslinking analysis. This work establishes the possible assembly mechanism of MACOM and MAC as an active m6A writer for RNA substrate recognition and modification.
2022-06-23 | PXD028456 |
Project description:Retroviral integration is catalyzed by a tetramer of integrase (IN) assembled on viral DNA ends in a stable complex, known as the intasome. How the intasome interfaces with chromosomal DNA, which exists in the form of nucleosomal arrays, is currently unknown. Here we show that the prototype foamy virus (PFV) intasome is proficient at stable capture of nucleosomes as targets for integration. Single-particle cryo-electron microscopy (EM) reveals a multivalent intasome-nucleosome interface involving both gyres of nucleosomal DNA and one H2A-H2B heterodimer. While the histone octamer remains intact, the DNA is lifted from the surface of the H2A-H2B heterodimer to allow integration at strongly preferred superhelix location (SHL) ±3.5 positions. Amino acid substitutions disrupting these contacts impinge on the ability of the intasome to engage nucleosomes in vitro and redistribute viral integration sites on the genomic scale. Our findings elucidate the molecular basis for nucleosome capture by the viral DNA recombination machinery and the underlying nucleosome plasticity that allows integration.
2015-06-10 | GSE67730 | GEO
Project description:In all branches of life, stalled translation intermediates are recognized and processed by ribosome-associated quality control (RQC) pathways. RQC begins with the splitting of stalled ribosomes, leaving an unfinished polypeptide still attached to the large subunit. Ancient and conserved NEMF family RQC proteins target these incomplete proteins for degradation by the addition of C-terminal "tails." How such tailing can occur without the regular suite of translational components is, however, unclear. Using single-particle cryo-electron microscopy (EM) of native complexes, we show that C-terminal tailing in Bacillus subtilis is mediated by NEMF protein RqcH in concert with RqcP, an Hsp15 family protein. Our structures reveal how these factors mediate tRNA movement across the ribosomal 50S subunit to synthesize polypeptides in the absence of mRNA or the small subunit.
2020-12-28 | GSE152592 | GEO