scholarly journals p300/CREB Binding Protein-Related Protein p270 Is a Component of Mammalian SWI/SNF Complexes

1998 ◽  
Vol 18 (6) ◽  
pp. 3596-3603 ◽  
Author(s):  
Peter B. Dallas ◽  
Ian Wayne Cheney ◽  
Da-Wei Liao ◽  
Valerie Bowrin ◽  
Whitney Byam ◽  
...  
Keyword(s):  
Hormone Receptors ◽  
Binding Protein ◽  
Chromatin Modification ◽  
Cellular Protein ◽  
Cellular Proteins ◽  
Creb Binding Protein ◽  
Detailed Characterization ◽  
Molecular Masses ◽  
Histone Acetyltransferase Activity

ABSTRACT p300 and the closely related CREB binding protein (CBP) are transcriptional adaptors that are present in intracellular complexes with TATA binding protein (TBP) and bind to upstream activators including p53 and nuclear hormone receptors. They have intrinsic and associated histone acetyltransferase activity, suggesting that chromatin modification is an essential part of their role in regulating transcription. Detailed characterization of a panel of antibodies raised against p300/CBP has revealed the existence of a 270-kDa cellular protein, p270, distinct from p300 and CBP but sharing at least two independent epitopes with p300. The subset of p300/CBP-derived antibodies that cross-reacts with p270 consistently coprecipitates a series a cellular proteins with relative molecular masses ranging from 44 to 190 kDa. Purification and analysis of various proteins in this group reveals that they are components of the human SWI/SNF complex and that p270 is an integral member of this complex.

scholarly journals A New Family of Nuclear Receptor Coregulators That Integrate Nuclear Receptor Signaling through CREB-Binding Protein

2000 ◽  
Vol 20 (14) ◽  
pp. 5048-5063 ◽  
Author(s):  
Muktar A. Mahajan ◽  
Herbert H. Samuels
Keyword(s):  
Nuclear Receptor ◽  
Hormone Receptors ◽  
Binding Protein ◽  
Nuclear Hormone Receptors ◽  
Dependent Manner ◽  
Creb Binding Protein ◽  
Activation Domain ◽  
High Affinity ◽  
New Family ◽  
Nuclear Receptor Coregulators

ABSTRACT We describe the cloning and characterization of a new family of nuclear receptor coregulators (NRCs) which modulate the function of nuclear hormone receptors in a ligand-dependent manner. NRCs are expressed as alternatively spliced isoforms which may exhibit different intrinsic activities and receptor specificities. The NRCs are organized into several modular structures and contain a single functional LXXLL motif which associates with members of the steroid hormone and thyroid hormone/retinoid receptor subfamilies with high affinity. Human NRC (hNRC) harbors a potent N-terminal activation domain (AD1), which is as active as the herpesvirus VP16 activation domain, and a second activation domain (AD2) which overlaps with the receptor-interacting LXXLL region. The C-terminal region of hNRC appears to function as an inhibitory domain which influences the overall transcriptional activity of the protein. Our results suggest that NRC binds to liganded receptors as a dimer and this association leads to a structural change in NRC resulting in activation. hNRC binds CREB-binding protein (CBP) with high affinity in vivo, suggesting that hNRC may be an important functional component of a CBP complex involved in mediating the transcriptional effects of nuclear hormone receptors.

scholarly journals Characterization of aggregates of hepatitis C virus glycoproteins

1999 ◽  
Vol 80 (12) ◽  
pp. 3099-3107 ◽  
Author(s):  
Amélie Choukhi ◽  
André Pillez ◽  
Hervé Drobecq ◽  
Christian Sergheraert ◽  
Czeslaw Wychowski ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Binding Protein ◽  
Active Role ◽  
Cellular Protein ◽  
Host Cells ◽  
Waste Products ◽  
Functional Complex ◽  
Heterologous Expression Systems

Hepatitis C virus (HCV) encodes two glycoproteins, E1 and E2, which assemble in oligomeric structures. Studies of HCV glycoprotein assembly using heterologous expression systems have shown that these glycoproteins can follow two pathways: a productive pathway leading to the formation of a non-covalent heterodimer; and a non-productive pathway leading to the formation of large disulfide-linked aggregates. The non-covalent HCV glycoprotein complex is probably the functional complex which plays an active role in the entry process in host cells. The aggregates are believed to be waste products; however, one can imagine that, in infected cells, they could provide HCV glycoproteins with additional functions. To further understand the potential role played by HCV glycoprotein aggregates in HCV infection, a MAb (H14) was produced which specifically recognizes these aggregates but not the non-covalent E1E2 heterodimer. The H14 epitope was shown to be present on both HCV glycoproteins and was sensitive to deglycosylation. An additional characterization of HCV glycoprotein aggregates, with the help of MAb H14, indicates that they share an epitope with a cellular protein called Mac-2 binding protein. The presence of such an epitope on HCV glycoprotein aggregates could potentially lead to the production of autoantibodies recognizing Mac-2 binding protein in HCV-infected patients.

scholarly journals The transcriptional integrator CREB-binding protein mediates positive cross talk between nuclear hormone receptors and the hematopoietic bZip protein p45/NF-E2.

1997 ◽  
Vol 17 (3) ◽  
pp. 1407-1416 ◽  
Author(s):  
X Cheng ◽  
M J Reginato ◽  
N C Andrews ◽  
M A Lazar
Keyword(s):  
Cross Talk ◽  
Protein Interactions ◽  
Leucine Zipper ◽  
Hormone Receptors ◽  
Binding Protein ◽  
Nuclear Hormone Receptors ◽  
Creb Binding Protein ◽  
Hormone Action ◽  
Interaction Domain ◽  
Bzip Protein

Thyroid hormone (T3) and retinoic acid (RA) play important roles in erythropoiesis. We found that the hematopoietic cell-specific bZip protein p45/NF-E2 interacts with T3 receptor (TR) and RA receptor (RAR) but not retinoid X receptor. The interaction is between the DNA-binding domain of the nuclear receptor and the leucine zipper region of p45/NF-E2 but is markedly enhanced by cognate ligand. Remarkably, ligand-dependent transactivation by TR and RAR is markedly potentiated by p45/NF-E2. This effect of p45/NF-E2 is prevented by maf-like protein p18, which functions positively as a heterodimer with p45/NF-E2 on DNA. Potentiation of hormone action by p45/NF-E2 requires its activation domain, which interacts strongly with the multifaceted coactivator cyclic AMP response element protein-binding protein (CBP). The region of CBP which interacts with p45/NF-E2 is the same interaction domain that mediates inhibition of hormone-stimulated transcription by AP1 transcription factors. Overexpression of the bZip interaction domain of CBP specifically abolishes the positive cross talk between TR and p45/NF-E2. Thus, positive cross talk between p45/NF-E2 and nuclear hormone receptors requires direct protein-protein interactions between these factors and with CBP, whose integration of positive signals from two transactivation domains provides a novel mechanism for potentiation of hormone action in hematopoietic cells.

scholarly journals A Role for CREB Binding Protein and p300 Transcriptional Coactivators in Ets-1 Transactivation Functions

1998 ◽  
Vol 18 (4) ◽  
pp. 2218-2229 ◽  
Author(s):  
Cheng Yang ◽  
Linda H. Shapiro ◽  
Morris Rivera ◽  
Alok Kumar ◽  
Paul K. Brindle
Keyword(s):  
Binding Protein ◽  
Critical Role ◽  
Specific Inhibitor ◽  
Creb Binding Protein ◽  
Rich Region ◽  
Adenovirus E1a ◽  
Synergistic Interactions ◽  
Nuclear Complex ◽  
Transcriptional Coactivators ◽  
Histone Acetyltransferase Activity

ABSTRACT The Ets-1 transcription factor plays a critical role in cell growth and development, but the means by which it activates transcription are still unclear (J. C. Bories, D. M. Willerford, D. Grevin, L. Davidson, A. Camus, P. Martin, D. Stehelin, F. W. Alt, and J. C. Borles, Nature 377:635–638, 1995; N. Muthusamy, K. Barton, and J. M. Leiden, Nature 377:639–642, 1995). Here we show that Ets-1 binds the transcriptional coactivators CREB binding protein (CBP) and the related p300 protein (together referred to as CBP/p300) and that this interaction is required for specific Ets-1 transactivation functions. The Ets-1- and c-Myb-dependent aminopeptidase N (CD13/APN) promoter and an Ets-1-dependent artificial promoter were repressed by adenovirus E1A, a CBP/p300-specific inhibitor. Furthermore, Ets-1 activity was potentiated by CBP and p300 overexpression. The transactivation function of Ets-1 correlated with its ability to bind an N-terminal cysteine- and histidine-rich region spanning CBP residues 313 to 452. Ets-1 also bound a second cysteine- and histidine-rich region of CBP, between residues 1449 and 1892. Both Ets-1 and CBP/p300 formed a stable immunoprecipitable nuclear complex, independent of DNA binding. This Ets-1–CBP/p300 immunocomplex possessed histone acetyltransferase activity, consistent with previous findings that CBP/p300 is associated with such enzyme activity. Our results indicate that CBP/p300 may mediate antagonistic and synergistic interactions between Ets-1 and other transcription factors that use CBP/p300 as a coactivator, including c-Myb and AP-1.

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