scholarly journals Novel functional insights revealed by distinct protein-protein interactions of the residual SWI/SNF complex in SMARCA4-deficient small cell carcinoma of the ovary, hypercalcemic type

2019 ◽  
Author(s):  
Elizabeth A. Raupach ◽  
Krystine Garcia-Mansfield ◽  
Ritin Sharma ◽  
Apurva M. Hegde ◽  
Victoria David-Dirgo ◽  
...  
Keyword(s):  
Cell Lines ◽  
Chromatin Remodeling ◽  
Protein Interactions ◽  
Rna Processing ◽  
Small Cell ◽  
Wild Type ◽  
Protein Protein Interactions ◽  
Functional Consequences ◽  
Carcinoma Of The Ovary ◽  
Inactivating Mutations

AbstractChromatin remodeling plays a critical role in tumor suppression as demonstrated by 20% of human cancers bearing inactivating mutations in SWI/SNF chromatin remodeling complex members. Mutations in different SWI/SNF subunits drive a variety of adult and pediatric tumor types, including non-small cell lung cancers, rhabdoid tumors, medulloblastomas, and ovarian cancers. Small cell carcinoma of the ovary hypercalcemic type (SCCOHT) is an aggressive subtype of ovarian cancer occurring in young women. Nearly all (>98%) SCCOHTs have inactivating mutations in SMARCA4, which encodes 1 of 2 mutually exclusive catalytic subunits of the SWI/SNF complex. Less than half of SCCOHT patients survive 5 years despite aggressive surgery and multimodal chemotherapy. Empirical support for effective SCCOHT treatments is scarce, in part because of the poor understanding of SCCOHT tumorigenesis. To gain insight into the functional consequences of SWI/SNF subunit loss, we defined SWI/SNF composition and its protein-protein interactions (PPIs) by immunoprecipitation and mass spectrometry (IP-MS) of SWI/SNF subunits in 3 SCCOHT cell lines. Comparing these results to a cell line containing a wild-type SWI/SNF complex, the interaction of most canonical core SWI/SNF subunits was observed in all SCCOHT cell lines at a lower abundance. The SCCOHT SWI/SNF also lacked ATPase module subunits and showed a drastic reduction in PBAF-specific subunit interactions. The wild-type and SCCOHT SWI/SNF subunits immunoprecipitated a shared set of 26 proteins, including core SWI/SNF subunits and RNA processing proteins. We observed 131 proteins exclusively interacting with the wild-type SWI/SNF complex including isoform-specific SWI/SNF subunits, members of the NuRD complex, and members of the MLL3/4 complex. We observed 60 PPIs exclusive to the SCCOHT residual SWI/SNF shared in at least 2 of the 3 SCCOHT cell lines, including many proteins involved in RNA processing. Differential interactions with the residual SWI/SNF complex in SCCOHT may further elucidate altered functional consequences of SMARCA4 mutations in these tumors as well as identify synthetic lethal targets that translate to other SWI/SNF-deficient tumors.

scholarly journals Regulating SWI/SNF Subunit Levels via Protein-Protein Interactions and Proteasomal Degradation: BAF155 and BAF170 Limit Expression of BAF57

2005 ◽  
Vol 25 (20) ◽  
pp. 9016-9027 ◽  
Author(s):  
Jianguang Chen ◽  
Trevor K. Archer
Keyword(s):  
Chromatin Remodeling ◽  
Protein Interactions ◽  
Wild Type ◽  
Protein Protein Interactions ◽  
Physiological Mechanisms ◽  
Protein Levels ◽  
Chromatin Remodeling Complex ◽  
Exogenous Expression ◽  
Protein Components ◽  
Enzyme Complexes

ABSTRACT The mammalian SWI/SNF chromatin remodeling complex, whose function is of critical importance in transcriptional regulation, contains approximately 10 protein components. The expression levels of the core SWI/SNF subunits, including BRG1/Brm, BAF155, BAF170, BAF60, hSNF/Ini1, and BAF57, are stoichiometric, with few to no unbound molecules in the cell. Here we report that exogenous expression of the wild type or certain deletion mutants of BAF57, a key subunit that mediates the interaction between the remodeling complex and transcription factors, results in diminished expression of endogenous BAF57. This down-regulation process is mediated by an increase in proteasome-dependent degradation of the BAF57 protein. Furthermore, the protein levels of BAF155/170 dictate the maximum cellular amount of BAF57. We mapped the domains responsible for the interaction between BAF57 and BAF155 and demonstrated that protein-protein interactions between them play an important role in this regulatory process. These findings provide insights into the physiological mechanisms responsible for maintaining the proper stoichiometric levels of the protein components comprising multimeric enzyme complexes.

scholarly journals PF16 encodes a protein with armadillo repeats and localizes to a single microtubule of the central apparatus in Chlamydomonas flagella.

1996 ◽  
Vol 132 (3) ◽  
pp. 359-370 ◽  
Author(s):  
E F Smith ◽  
P A Lefebvre
Keyword(s):  
Protein Interactions ◽  
Insertional Mutagenesis ◽  
Flagellar Motility ◽  
Wild Type ◽  
Protein Protein Interactions ◽  
Cellular Functions ◽  
Central Pair ◽  
Central Apparatus ◽  
Immunofluorescence Labeling ◽  
Armadillo Repeats

Several studies have indicated that the central pair of microtubules and their associated structures play a significant role in regulating flagellar motility. To begin a molecular analysis of these components we have generated central apparatus-defective mutants in Chlamydomonas reinhardtii using insertional mutagenesis. One paralyzed mutant recovered in our screen, D2, is an allele of a previously identified mutant, pf16. Mutant cells have paralyzed flagella, and the C1 microtubule of the central apparatus is missing in isolated axonemes. We have cloned the wild-type PF16 gene and confirmed its identity by rescuing pf16 mutants upon transformation. The rescued pf16 cells were wild-type in motility and in axonemal ultrastructure. A full-length cDNA clone for PF16 was obtained and sequenced. Database searches using the predicted 566 amino acid sequence of PF16 indicate that the protein contains eight contiguous armadillo repeats. A number of proteins with diverse cellular functions also contain armadillo repeats including pendulin, Rch1, importin, SRP-1, and armadillo. An antibody was raised against a fusion protein expressed from the cloned cDNA. Immunofluorescence labeling of wild-type flagella indicates that the PF16 protein is localized along the length of the flagella while immunogold labeling further localizes the PF16 protein to a single microtubule of the central pair. Based on the localization results and the presence of the armadillo repeats in this protein, we suggest that the PF16 gene product is involved in protein-protein interactions important for C1 central microtubule stability and flagellar motility.

scholarly journals The functional impact of alternative splicing in cancer

2016 ◽  
Author(s):  
Héctor Climente-González ◽  
Eduard Porta-Pardo ◽  
Adam Godzik ◽  
Eduardo Eyras
Keyword(s):  
Alternative Splicing ◽  
Negative Correlation ◽  
Protein Interactions ◽  
Somatic Mutations ◽  
Protein Domain ◽  
Protein Protein Interactions ◽  
Systematic Analysis ◽  
Functional Impact ◽  
Functional Consequences ◽  
Functional Transformations

SummaryAlternative splicing changes are frequently observed in cancer and are starting to be recognized as important signatures for tumor progression and therapy. However, their functional impact and relevance to tumorigenesis remains mostly unknown. We carried out a systematic analysis to characterize the potential functional consequences of alternative splicing changes in thousands of tumor samples. This analysis revealed that a subset of alternative splicing changes affect protein domain families that are frequently mutated in tumors and potentially disrupt protein protein interactions in cancer-related pathways. Moreover, there was a negative correlation between the number of these alternative splicing changes in a sample and the number of somatic mutations in drivers. We propose that a subset of the alternative splicing changes observed in tumors may represent independent oncogenic processes that could be relevant to explain the functional transformations in cancer and some of them could potentially be considered alternative splicing drivers (AS-drivers).

scholarly journals A Specificity and Targeting Subunit of a Human SWI/SNF Family-Related Chromatin-Remodeling Complex

2000 ◽  
Vol 20 (23) ◽  
pp. 8879-8888 ◽  
Author(s):  
Zuqin Nie ◽  
Yutong Xue ◽  
Dafeng Yang ◽  
Sharleen Zhou ◽  
Bonnie J. Deroo ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Chromatin Remodeling ◽  
Protein Interactions ◽  
Transcriptional Activation ◽  
Gene Activation ◽  
Dna Interaction ◽  
Protein Protein Interactions ◽  
Baf Complex ◽  
Chromatin Remodeling Complexes

ABSTRACT The SWI/SNF family of chromatin-remodeling complexes facilitates gene activation by assisting transcription machinery to gain access to targets in chromatin. This family includes BAF (also called hSWI/SNF-A) and PBAF (hSWI/SNF-B) from humans and SWI/SNF and Rsc fromSaccharomyces cerevisiae. However, the relationship between the human and yeast complexes is unclear because all human subunits published to date are similar to those of both yeast SWI/SNF and Rsc. Also, the two human complexes have many identical subunits, making it difficult to distinguish their structures or functions. Here we describe the cloning and characterization of BAF250, a subunit present in human BAF but not PBAF. BAF250 contains structural motifs conserved in yeast SWI1 but not in any Rsc components, suggesting that BAF is related to SWI/SNF. BAF250 is also a homolog of the Drosophila melanogaster Osa protein, which has been shown to interact with a SWI/SNF-like complex in flies. BAF250 possesses at least two conserved domains that could be important for its function. First, it has an AT-rich DNA interaction-type DNA-binding domain, which can specifically bind a DNA sequence known to be recognized by a SWI/SNF family-related complex at the β-globin locus. Second, BAF250 stimulates glucocorticoid receptor-dependent transcriptional activation, and the stimulation is sharply reduced when the C-terminal region of BAF250 is deleted. This region of BAF250 is capable of interacting directly with the glucocorticoid receptor in vitro. Our data suggest that BAF250 confers specificity to the human BAF complex and may recruit the complex to its targets through either protein-DNA or protein-protein interactions.

scholarly journals The 14-3-3 Proteins as Important Allosteric Regulators of Protein Kinases

2020 ◽  
Vol 21 (22) ◽  
pp. 8824
Author(s):  
Veronika Obsilova ◽  
Tomas Obsil
Keyword(s):  
Protein Interactions ◽  
Cell Cycle Progression ◽  
State Of The Art ◽  
Review Article ◽  
Protein Protein Interactions ◽  
Cycle Progression ◽  
Kinase Regulation ◽  
Functional Consequences ◽  
Allosteric Regulators ◽  
Structural Aspects

Phosphorylation by kinases governs many key cellular and extracellular processes, such as transcription, cell cycle progression, differentiation, secretion and apoptosis. Unsurprisingly, tight and precise kinase regulation is a prerequisite for normal cell functioning, whereas kinase dysregulation often leads to disease. Moreover, the functions of many kinases are regulated through protein–protein interactions, which in turn are mediated by phosphorylated motifs and often involve associations with the scaffolding and chaperon protein 14-3-3. Therefore, the aim of this review article is to provide an overview of the state of the art on 14-3-3-mediated kinase regulation, focusing on the most recent mechanistic insights into these important protein–protein interactions and discussing in detail both their structural aspects and functional consequences.

scholarly journals The Effect of Proline cis-trans Isomerization on the Folding of the C-Terminal SH2 Domain from p85

2019 ◽  
Vol 21 (1) ◽  
pp. 125
Author(s):  
Francesca Troilo ◽  
Francesca Malagrinò ◽  
Lorenzo Visconti ◽  
Angelo Toto ◽  
Stefano Gianni
Keyword(s):  
Protein Interactions ◽  
Specific Interaction ◽  
Sh2 Domain ◽  
Regulatory Subunit ◽  
Wild Type ◽  
Protein Protein Interactions ◽  
Sh2 Domains ◽  
Trans Isomerization ◽  
A Site ◽  
Kinetics Of

SH2 domains are protein domains that modulate protein–protein interactions through a specific interaction with sequences containing phosphorylated tyrosines. In this work, we analyze the folding pathway of the C-terminal SH2 domain of the p85 regulatory subunit of the protein PI3K, which presents a proline residue in a cis configuration in the loop between the βE and βF strands. By employing single and double jump folding and unfolding experiments, we demonstrate the presence of an on-pathway intermediate that transiently accumulates during (un)folding. By comparing the kinetics of folding of the wild-type protein to that of a site-directed variant of C-SH2 in which the proline was replaced with an alanine, we demonstrate that this intermediate is dictated by the peptidyl prolyl cis-trans isomerization. The results are discussed in the light of previous work on the effect of peptidyl prolyl cis-trans isomerization on folding events.

scholarly journals Targeting RNA Binding Proteins Involved in Neurodegeneration

2013 ◽  
Vol 18 (9) ◽  
pp. 967-983 ◽  
Author(s):  
Maurizio Romano ◽  
Emanuele Buratti
Keyword(s):  
Protein Interactions ◽  
Rna Processing ◽  
Noncoding Rna ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Correct Identification ◽  
Protein Protein Interactions ◽  
Aggregation Processes ◽  
Cellular Pathways ◽  
Screening Approaches

Dysfunctions at the level of RNA processing have recently been shown to play a fundamental role in the pathogenesis of many neurodegenerative diseases. Several proteins responsible for these dysfunctions (TDP-43, FUS/TLS, and hnRNP A/Bs) belong to the nuclear class of heterogeneous ribonucleoproteins (hnRNPs) that predominantly function as general regulators of both coding and noncoding RNA metabolism. The discovery of the importance of these factors in mediating neuronal death has represented a major paradigmatic shift in our understanding of neurodegenerative processes. As a result, these discoveries have also opened the way toward novel biomolecular screening approaches in our search for therapeutic options. One of the major hurdles in this search is represented by the correct identification of the most promising targets to be prioritized. These may include aberrant aggregation processes, protein-protein interactions, RNA-protein interactions, or specific cellular pathways altered by disease. In this review, we discuss these four major options together with their various advantages and drawbacks.

scholarly journals Malignant Peritoneal Mesothelioma Interactome with 417 Novel Protein-Protein Interactions

2021 ◽  
Author(s):  
Kalyani B. Karunakaran ◽  
Madhavi K. Ganapathiraju
Keyword(s):  
Gene Expression ◽  
Cell Lines ◽  
Protein Interactions ◽  
Cellular Localization ◽  
Expression Profiles ◽  
Abdominal Cavity ◽  
Peritoneal Mesothelioma ◽  
Pleural Mesothelioma ◽  
Malignant Peritoneal Mesothelioma ◽  
Protein Protein Interactions

Abstract Malignant peritoneal mesothelioma (MPeM) is an aggressive cancer affecting the peritoneal lining of the abdominal cavity and intra-abdominal organs, with a median survival of ~2.5 years. We constructed an ‘MPeM interactome’ with over 400 computationally predicted protein-protein interactions (PPIs) and over 4,700 known PPIs of 59 literature-curated genes whose activity affects MPeM. Known PPIs of the 59 MPeM-associated genes were derived from BioGRID and HPRD databases. Novel PPIs were predicted by applying the HiPPIP algorithm, which computes features of protein pairs such as cellular localization, molecular function, biological process membership, genomic location of the gene, and gene expression in microarray experiments, and classifies the pairwise features as interacting or non-interacting based on a random forest model. 75.6% of the interactome and 65% of the novel interactors in it were supported by transcriptomic evidence in rodent and human peritoneal mesothelioma/mesothelial cell lines and tumor specimens. 152 drugs targeted 427 proteins in the MPeM interactome. Comparative transcriptome analysis of peritoneal mesothelioma-associated versus drug-induced gene expression profiles revealed 39 repurposable drugs, out of which 29 were effective against peritoneal/pleural mesothelioma and/or peritoneal metastasis/primary peritoneal cancer in clinical trials, animal models or cell lines. Functional modules of chromosomal segregation, transcriptional deregulation, positive regulation of IL-6 production and hematopoiesis were identified from the interactome. Genes with tissue-specific expression in 2 sites of extramedullary hematopoiesis (spleen and thymus) and those correlated with unfavorable prognosis in liver, renal, pancreatic and lung cancers were noted. MPeM interactome showed extensive overlap with the malignant pleural mesothelioma (MPM) interactome and MPM cell line expression profiles. Our findings demonstrate the utility of the MPeM interactome in discovering systems-level functional links among MPeM genes and generating clinically translatable results such as repurposed drugs.

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