Human p53 interating protein ID
Ontology highlight
ABSTRACT:
INSTRUMENT(S): LTQ Orbitrap
ORGANISM(S): Homo Sapiens (human)
TISSUE(S): Lung Endothelium
DISEASE(S): Lung Cancer
SUBMITTER: 
vishwanatha chandrahas
LAB HEAD: Richard Anderson
PROVIDER: PXD012463 | Pride | 2019-01-29
REPOSITORIES: Pride
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Project description:The human TP53 gene is frequently mutated in tumors and cell lines. Unlike other tumor suppressors that are commonly inactivated by deletions or nonsense mutations, the majority of p53-mutations are missense point mutations that result in the expression of a full-length protein with an altered amino acid that has lost sequence specific DNA-binding. Expression of mutant p53 (mutp53) confers advantages to tumor cells and transcriptional regulation of several genes mediating the beneficial effects has been shown to play a role. However, molecular mechanisms of transcriptional regulation by mutp53 are still poorly understood. We used the glioblastoma-derived U-251 MG human cell line endogenously expressing mutp53 protein (R273H mutation) to analyze gene expression profiles on Agilent Whole Human Genome Microarray after transient and stable depletion of mutp53 expression. Gene expression data was correlated with a ChIP study on a custom tiling array to understand the contribution of endogenously expressed mutp53 to transcriptional regulation. This series of microarray experiments contains the gene expression profiles of glioblastoma-derived U-251 MG human cell lines engineered to constitutively express a p53-specific shRNA or scrambled control shRNA. To reverse the effect of mutp53 depletion, stable clones were modified by stable integration of a mutp53-R273H expression construct or empty pCDNA3 vector as a control. In addition, we performed gene expression analysis of U-251 MG cells transiently transfected with p53-specific siRNA or control siRNA (3 biological replicates each).
2012-12-10 | E-GEOD-35454 | biostudies-arrayexpress
Project description:The completion of the Plasmodium falciparum clone 3D7 genome provides a basis on which to conduct comparative proteomics studies of this human pathogen. Here, we applied a high-throughput proteomics approach to identify new potential drug and vaccine targets and to better understand the biology of this complex protozoan parasite. We characterized four stages of the parasite life cycle (sporozoites, merozoites, trophozoites and gametocytes) by multidimensional protein identification technology. Functional profiling of over 2,400 proteins agreed with the physiology of each stage. Unexpectedly, the antigenically variant proteins of var and rif genes, defined as molecules on the surface of infected erythrocytes, were also largely expressed in sporozoites. The detection of chromosomal clusters encoding co-expressed proteins suggested a potential mechanism for controlling gene expression. Keywords: ordered
2002-12-22 | E-GEOD-92 | biostudies-arrayexpress
Project description:Readthrough of a translation termination codon is regulated by ribosomal A site recognition and insertion of near-cognate tRNAs. Small molecules exist that mediate the incorporation of amino acids at the stop codon and the production of full-length, often functional protein but defining the actual amino acid that is incorporated remains a challenging area. We report on the development of a human cell model that can be used to determine whether rules can be developed using mass spectrometry that defines the type of amino acid that is placed at a premature termination codon during readthrough mediated by an aminoglycoside. The first premature termination codon we analysed contained the relatively common cancer-associated termination signal at codon 213 in the p53 gene. Although we could detect a tryptic peptide with the incorporation of an R at codon 213 in the presence of the aminoglycoside, there were no other tryptic peptides detected across codon 213 that could be recovered so we needed to create a more robust artificial premature stop codon model. P53 expression plasmids were developed that incorporate a string of single synthetic UGA (opal) stop codons at S127P128A129 within the relatively abundant tryptic p53 peptide 122-SVTCTYSPALNK-132. The treatment of cells stably expressing the p53-UGA129 mutation, treated with Gentamycin, followed by immunoprecipitation and trypsinization of p53, resulted in the identification R, W, or C within the tryptic peptide at codon-UGA129; as expected based on the two base pairing of the respective anticodons to UGA with R being the most abundant using all three codons. By contrast, incorporating the amber or ochre premature stop codons, UAA129 or UAG129 resulted in the incorporation of a Y or Q amino acid, again as expected based on the two base pairings to the anticodons, with Q being the most abundant. The incorporation of these amino acids at codons 127, 128, or 129 generally results in a p53 protein that is predicted to be ‘unfolded’ or inactive as defined by Molecular Dynamic Simulations. As such, the data also highlight the need in the future to not only produce novel small molecules that can read through premature termination codons but also the need to design methods to insert the required amino acid at the position that could result in a ‘wild-type’ functional protein.
2024-10-29 | PXD039307 | Pride
Project description:Advanced colorectal cancer (CRC) is an unresolved clinical problem. Epigenetic drugs belonging to the group of histone deacetylase inhibitors (HDACi) may combat CRC in rationally designed treatment schedules. Unfortunately, there is sparse evidence on molecular mechanisms and markers that determine cellular sensitivity to HDACi. Irinotecan is widely used to treat CRC and causes replication stress (RS) and DNA damage as topoisomerase-I inhibitor. We applied irinotecan and the class I HDACi entinostat (MS-275) to isogenic p53-positive and -negative CRC cells. Combinations of irinotecan and MS-275 evoke mitochondrial damage, caspase-mediated apoptosis, and RS-associated DNA damage synergistically and p53-dependently. Targeted mass spectrometry and immunoblot show that irinotecan induces phosphorylation, acetylation, and accumulation of p53 and its target genes. Addition of MS-275 augments the irinotecan-induced acetylation of C-terminal lysine residues of p53 but decreases its phosphorylation and p53 target gene induction. Furthermore, MS-275 increases the amount of acetylated p53 at mitochondria and dysregulates the expression of pro- and anti-apoptotic BCL2 proteins in irinotecan-treated cells. Regarding DNA repair, we see that MS-275 represses the homologous recombination (HR) filament protein RAD51, which limits DNA damage and pro-apoptotic effects of irinotecan. These data suggest that key class I HDAC-dependent functions of p53 in cells with RS are linked to mitochondrial damage and a breakdown of HR. Most importantly, combinations of irinotecan plus MS-275 also kill short-term primary CRC cell cultures and organoids from CRC patients but spare organoids of adjacent matched normal tissue. Thus, irinotecan/HDACi treatment is a promising new approach for the therapy of p53-proficient tumors with clinically tractable inhibitors.
2022-02-15 | PXD019999 | Pride
Project description:p53 is a pivotal tumor suppressor and a major barrier against cancer. We now report that silencing of the Hippo pathway tumor suppressors LATS1 and LATS2 in non-transformed mammary epithelial cells reduces p53 phosphorylation and increases its association with the p52 NF-κB subunit. Moreover, it partly shifts p53’s conformation and transcriptional output towards a state resembling cancer-associated p53 mutants, and endow p53 with the ability to promote cell migration. Notably, LATS1 and LATS2 are frequently downregulated in breast cancer; we propose that such downregulation might benefit cancer by converting p53 from a tumor suppressor into a tumor facilitator.
2018-10-25 | PXD003120 | Pride
Project description:The tetrameric tumor suppressor p53 represents a great challenge for 3D structural analysis due to its high degree of intrinsic disorder (ca. 40%). We developed and applied an integrative structural biology approach combining complementary techniques of structural mass spectrometry (MS), namely cross-linking mass spectrometry (XL-MS), protein footprinting, and hydrogen/deuterium exchange mass spectrometry (HDX-MS), with advanced protein structure prediction approaches to gain insights into the disordered C-terminal region of p53. Additionally, we evaluate possible differences in p53 regarding solvent accessibility and topology upon DNA binding. Our quantitative XL-MS and lysine labeling data show no major conformational differences in p53 between DNA-bound and DNA-free states. Integration of experimental data generate p53 models for p53’s intrinsically disordered regions (IDRs) that reflect substantial compaction of the molecule. Our models provide the most detailed description of the relationship between p53’s folded regions and IDRs that is available to date. The synergies between complementary structural MS techniques and computational modeling as pursued in our integrative approach is envisioned to serve as general strategy for studying intrinsically disordered proteins (IDPs) and IDRs.
2023-06-26 | PXD037030 | Pride
Project description:The tumor suppressor protein p53 is a transcription factor that is referred to as the “guardian of the genome” and plays an important role in cancer development. P53 is active as a tetramer; the S100β homodimer binds to the intrinsically disordered C-terminus of p53, affecting its transcriptional activity. The p53/S100β complex is regarded as highly promising therapeutic target in cancer. It has been suggested that S100β exerts its oncogenic effects by altering the p53 oligomeric state. Our aim was to study the structures and oligomerization behavior of different p53/S100β complexes by electrospray ionization mass spectrometry (ESI-MS), cross-linking mass spectrometry (XL-MS), and surface plasmon resonance (SPR). For this, wild-type p53 and single amino acid variants, representing different oligomeric states of p53 (tetrameric wild-type, dimeric L344A variant, and monomeric L344P variant) were individually investigated regarding their binding behavior towards S100β. The stoichiometry of the different p53/S100β complexes were determined by ESI-MS showing that tetrameric, dimeric, and monomeric p53 variants all bind to an S100β dimer. In addition, XL-MS revealed the topologies of the p53/S100β complexes to be independent of p53’s oligomeric state. With SPR, the thermodynamic parameters were determined for S100β binding to tetrameric, dimeric or monomeric p53 variants. Our data prove that the S100β homodimer binds to different oligomeric states of p53 with identical stoichiometries and similar binding affinities. This emphasizes the need for alternative explanations to describe the molecular mechanisms underlying p53/S100β interaction.
2022-10-14 | PXD029914 | Pride
Project description:Mutant p53 proteins, resulting form frequent TP53 tumor suppressor missense mutations, possess gain-of-function activities and are among the most widespread and robust oncoproteins in human tumors. They are potentially important but understudied therapeutic targets. No studies to date have distinguished common, therapeutically relevant mutant p53 gain-of-function effects, from effects specific to different mutant variants and cell backgrounds. Here we identify 26S proteasome machinery as the common downstream effector controlled by mutant p53s in Triple Negative Breast Cancer (TNBC - aggressive carcinomas with TP53 as the most frequently mutated locus) and conserved in other human cancers. We have identified this pathway using a combination of single-model, multi-method vertical analysis (whole cell proteome, RNA sequencing an ChIP sequencing) and multi-cell line, horizontal analysis of transcriptiomes. We found that different missense mutant p53s regardless of the cell background transcriptionaly activate whole 26S proteasome machinery. Proteasome activity is significantly increased in p53 mutant versus wild-type or knockdown/null status - in cellular and mouse models as well as in human breast tumors. Increased proteasome activity leads to inhibition of tumor suppressive pathways. The control of mutant p53 over proteasome transcription and activity results in the increased resistance to proteasome inhibitors. By combining the mutant p53 targeting agents and proteasome inhibitor we were able to overcome the “bounce-back” proteasome inhibitor resistance mechanism in mutant p53 bearing TNBC cells and xenografts in vivo.
2016-05-03 | PXD001673 | Pride
Project description:To evaluate the effect on gene expression by lincRNAs, we knocked down three lincRNAs and evaluated the gene expression by microarray analysis. Gene expression was measured in Hep3B cells transfected with siRNAs targeting the indicated lincRNAs or negative control siRNA and infected with adenovirus expressing p53 (Ad-p53) or LacZ (Ad-LacZ).
2012-08-01 | E-GEOD-39773 | biostudies-arrayexpress
Project description:The genomic binding sites of the transcription factor (TF) and tumour suppressor p53 are unusually diverse in regards to their chromatin features, including histone modifications, opening the possibility that chromatin provides context-dependence for p53 regulation. Here, we show that the ability of p53 to open chromatin and activate its target genes is indeed locally restricted by its cofactor Trim24. Trim24 binds to both p53 and unmethylated lysine 4 of histone H3, thereby preferentially locating to those p53 sites that reside in closed chromatin, while it is deterred from accessible chromatin by lysine 4 methylation. The presence of Trim24 increases cell viability upon stress and enables p53 to impact gene expression as a function of the local chromatin state. These findings link histone methylation to p53 function and illustrate how specificity in chromatin can be achieved, not by TF-intrinsic sensitivity to histone modifications, but by employing chromatin-sensitive cofactors which locally modulate TF function.
2023-05-05 | PXD039553 | Pride