scholarly journals Yeast Isw1p Forms Two Separable Complexes In Vivo

2003 ◽  
Vol 23 (1) ◽  
pp. 80-91 ◽  
Author(s):  
Jay C. Vary, ◽  
Vamsi K. Gangaraju ◽  
Jun Qin ◽  
Carolyn Church Landel ◽  
Charles Kooperberg ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcriptional Regulation ◽  
Chromatin Remodeling ◽  
Elevated Temperatures ◽  
Cellular Processes ◽  
Biochemical Assays ◽  
Associated Proteins ◽  
Chromatin Remodeling Complexes ◽  
Specific Activities

ABSTRACT There are several classes of ATP-dependent chromatin remodeling complexes, which modulate the structure of chromatin to regulate a variety of cellular processes. The budding yeast, Saccharomyces cerevisiae, encodes two ATPases of the ISWI class, Isw1p and Isw2p. Previously Isw1p was shown to copurify with three other proteins. Here we identify these associated proteins and show that Isw1p forms two separable complexes in vivo (designated Isw1a and Isw1b). Biochemical assays revealed that while both have equivalent nucleosome-stimulated ATPase activities, Isw1a and Isw1b differ in their abilities to bind to DNA and nucleosomal substrates, which possibly accounts for differences in specific activities in nucleosomal spacing and sliding. In vivo, the two Isw1 complexes have overlapping functions in transcriptional regulation of some genes yet distinct functions at others. In addition, these complexes show different contributions to cell growth at elevated temperatures.

scholarly journals FBXO32 links ubiquitination to epigenetic reprograming of melanoma cells

2021 ◽  
Author(s):  
Nadia Habel ◽  
Najla El-Hachem ◽  
Frédéric Soysouvanh ◽  
Hanene Hadhiri-Bzioueche ◽  
Serena Giuliano ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Target Gene ◽  
Tumor Development ◽  
Melanoma Cells ◽  
Complex Activity ◽  
Cellular Processes ◽  
Chromatin Remodeling Complex ◽  
Chromatin Remodeling Complexes ◽  
Proliferation And Invasion

AbstractUbiquitination by serving as a major degradation signal of proteins, but also by controlling protein functioning and localization, plays critical roles in most key cellular processes. Here, we show that MITF, the master transcription factor in melanocytes, controls ubiquitination in melanoma cells. We identified FBXO32, a component of the SCF E3 ligase complex as a new MITF target gene. FBXO32 favors melanoma cell migration, proliferation, and tumor development in vivo. Transcriptomic analysis shows that FBXO32 knockdown induces a global change in melanoma gene expression profile. These include the inhibition of CDK6 in agreement with an inhibition of cell proliferation and invasion upon FBXO32 silencing. Furthermore, proteomic analysis identifies SMARC4, a component of the chromatin remodeling complexes BAF/PBAF, as a FBXO32 partner. FBXO32 and SMARCA4 co-localize at loci regulated by FBXO32, such as CDK6 suggesting that FBXO32 controls transcription through the regulation of chromatin remodeling complex activity. FBXO32 and SMARCA4 are the components of a molecular cascade, linking MITF to epigenetics, in melanoma cells.

scholarly journals Mutations in Chromatin Components Suppress a Defect of Gcn5 Protein in Saccharomyces cerevisiae

1998 ◽  
Vol 18 (2) ◽  
pp. 1049-1054 ◽  
Author(s):  
José Pérez-Martín ◽  
Alexander D. Johnson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Weight ◽  
Transcriptional Regulation ◽  
Chromatin Remodeling ◽  
Histone Acetyltransferase ◽  
Histone Gene ◽  
High Molecular Weight Complex ◽  
Nuclear Histone ◽  
Full Activation

ABSTRACT The yeast GCN5 gene encodes the catalytic subunit of a nuclear histone acetyltransferase and is part of a high-molecular-weight complex involved in transcriptional regulation. In this paper we show that full activation of the HOpromoter in vivo requires the Gcn5 protein and that defects in this protein can be suppressed by deletion of the RPD3 gene, which encodes a histone deacetylase. These results suggest an interplay between acetylation and deacetylation of histones in the regulation of the HO gene. We also show that mutations in either the H4 or the H3 histone gene, as well as mutations in the SIN1gene, which encodes an HMG1-like protein, strongly suppress the defects produced by the gcn5 mutant. These results suggest a hierarchy of action in the process of chromatin remodeling.

scholarly journals Emerging Roles of BRD7 in Pathophysiology

2020 ◽  
Vol 21 (19) ◽  
pp. 7127
Author(s):  
Sang Won Park ◽  
Junsik M. Lee
Keyword(s):  
Cell Cycle ◽  
Transcriptional Regulation ◽  
Nasopharyngeal Carcinoma ◽  
Chromatin Remodeling ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Cellular Processes ◽  
Regulation Of Metabolism ◽  
Associated Proteins ◽  
Obesity And Cancer

Bromodomain is a conserved structural module found in many chromatin-associated proteins. Bromodomain-containing protein 7 (BRD7) is a member of the bromodomain-containing protein family, and was discovered two decades ago as a protein that is downregulated in nasopharyngeal carcinoma. Since then, BRD7 has been implicated in a variety of cellular processes, including chromatin remodeling, transcriptional regulation, and cell cycle progression. Decreased BRD7 activity underlies the pathophysiological properties of various diseases in different organs. BRD7 plays an important role in the pathogenesis of many cancers and, more recently, its roles in the regulation of metabolism and obesity have also been highlighted. Here, we review the involvement of BRD7 in a variety of pathophysiological conditions, with a focus on glucose homeostasis, obesity, and cancer.

Nucleosome mobilization and positioning by ISWI-containing chromatin-remodeling factors

2001 ◽  
Vol 114 (14) ◽  
pp. 2561-2568
Author(s):  
Gernot Längst ◽  
Peter B. Becker
Keyword(s):  
Transcriptional Regulation ◽  
Chromatin Remodeling ◽  
Chromosome Structure ◽  
Dynamic Properties ◽  
Chromatin Assembly ◽  
Functional Characteristics ◽  
Cellular Processes

ATP-dependent chromatin-remodeling machines of the SWI/SNF family are involved in many cellular processes in eukaryotic nuclei, such as transcription, replication, repair and recombination. Remodeling factors driven by the ATPase ISWI make up a subgroup of this family that exhibits defined mechanistic and functional characteristics. ISWI-induced nucleosome mobility endows nucleosomal arrays with dynamic properties and recent results suggest that ISWI-type remodelers have diverse functions that range from transcriptional regulation to chromatin assembly and maintenance of chromosome structure.

Comparison of the mitochondrial endonucleases from Neurospora crassa and Saccharomyces cerevisiae

1985 ◽  
Vol 31 (7) ◽  
pp. 654-656 ◽  
Author(s):  
Richard G. von Tigerstrom ◽  
Sheilah Stelmaschuk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Neurospora Crassa ◽  
Mode Of Action ◽  
Elevated Temperatures ◽  
Physiological Role ◽  
Intracellular Location ◽  
Substrate Specificities ◽  
Structural Differences ◽  
Specific Activities

The endonucleases from Neurospora crassa and Saccharomyces cerevisiae are not closely related antigenically. They also differ with respect to their activity at pH 8, their degree of hydrophobicity, and their sensitivity to elevated temperatures. However, the two nucleases have similar specific activities, are inhibited by EDTA, and have nearly identical substrate specificities. Since the enzymes also have the same mode of action and intracellular location, these similarities may indicate that they have the same physiological role despite their structural differences.

scholarly journals ZapA tetramerization is required for midcell localization and ZapB interaction in Escherichia coli

2019 ◽  
Author(s):  
Nils Y. Meiresonne ◽  
Tanneke den Blaauwen
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Bacterial Cell Division ◽  
Cellular Processes ◽  
Interaction Partners ◽  
Associated Proteins

AbstractBacterial cell division is guided by FtsZ treadmilling precisely at midcell. FtsZ itself is regulated by FtsZ associated proteins (Zaps) that couple it to different cellular processes. ZapA is known to enhance FtsZ bundling but also forms the synchronizing link with chromosome segregation through ZapB and matS bound MatP. ZapA exists as dimers and tetramers in the cell. Using the ZapAI83E mutant that only forms dimers, this paper investigates the effects of ZapA multimerization state on its interaction partners and cell division. By employing (fluorescence) microscopy and Förster Resonance Energy Transfer in vivo it is shown that; dimeric ZapA is unable to complement a zapA deletion strain and localizes diffusely through the cell but still interacts with FtsZ that is not part of the cell division machinery. Dimeric ZapA is unable to recruit ZapB, which localizes in its presence unipolarly in the cell. Interestingly, the localization profiles of the chromosome and unipolar ZapB anticorrelate. The work presented here confirms previously reported in vitro effects of ZapA multimerization in vivo and further places it in a broader context by revealing the strong implications for ZapB localization and ter linkage.

scholarly journals Structure of theArabidopsisTOPLESS corepressor provides insight into the evolution of transcriptional repression

2017 ◽  
Vol 114 (30) ◽  
pp. 8107-8112 ◽  
Author(s):  
Raquel Martin-Arevalillo ◽  
Max H. Nanao ◽  
Antoine Larrieu ◽  
Thomas Vinos-Poyo ◽  
David Mast ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Transcriptional Repression ◽  
Site Directed Mutagenesis ◽  
Crystallographic Structure ◽  
Hormone Signaling ◽  
Chromatin Remodeling Complexes ◽  
Insight Into ◽  
Similar Domain

Transcriptional repression involves a class of proteins called corepressors that link transcription factors to chromatin remodeling complexes. In plants such asArabidopsis thaliana, the most prominent corepressor is TOPLESS (TPL), which plays a key role in hormone signaling and development. Here we present the crystallographic structure of theArabidopsisTPL N-terminal region comprising the LisH and CTLH (C-terminal to LisH) domains and a newly identified third region, which corresponds to a CRA domain. Comparing the structure of TPL with the mammalian TBL1, which shares a similar domain structure and performs a parallel corepressor function, revealed that the plant TPLs have evolved a new tetramerization interface and unique and highly conserved surface for interaction with repressors. Using site-directed mutagenesis, we validated those surfaces in vitro and in vivo and showed that TPL tetramerization and repressor binding are interdependent. Our results illustrate how evolution used a common set of protein domains to create a diversity of corepressors, achieving similar properties with different molecular solutions.

The Drosophila trithorax group proteins BRM, ASH1 and ASH2 are subunits of distinct protein complexes

Development ◽  
1998 ◽  
Vol 125 (20) ◽  
pp. 3955-3966 ◽  
Author(s):  
O. Papoulas ◽  
S.J. Beek ◽  
S.L. Moseley ◽  
C.M. McCallum ◽  
M. Sarte ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Protein Complexes ◽  
Dominant Negative ◽  
Homeotic Genes ◽  
Atpase Subunit ◽  
Trithorax Group ◽  
Chromatin Remodeling Complexes ◽  
Trithorax Group Proteins ◽  
Drosophila Embryos

The trithorax group gene brahma (brm) encodes an activator of Drosophila homeotic genes that functions as the ATPase subunit of a large protein complex. To determine if BRM physically interacts with other trithorax group proteins, we purified the BRM complex from Drosophila embryos and analyzed its subunit composition. The BRM complex contains at least seven major polypeptides. Surprisingly, the majority of the subunits of the BRM complex are not encoded by trithorax group genes. Furthermore, a screen for enhancers of a dominant-negative brm mutation identified only one trithorax group gene, moira (mor), that appears to be essential for brm function in vivo. Four of the subunits of the BRM complex are related to subunits of the yeast chromatin remodeling complexes SWI/SNF and RSC. The BRM complex is even more highly related to the human BRG1 and hBRM complexes, but lacks the subunit heterogeneity characteristic of these complexes. We present biochemical evidence for the existence of two additional complexes containing trithorax group proteins: a 2 MDa ASH1 complex and a 500 kDa ASH2 complex. These findings suggest that BRM plays a role in chromatin remodeling that is distinct from the function of most other trithorax group proteins.

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