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B, and Serum Response Factor as Novel Target Molecules of the Cancer-Amplified Transcription Coactivator ASC-2
Center for Ligand and Transcription (S.-K.L., S.-Y.N., S.-Y.J., J.H.C., Y.C.L., J.W.L.) Department of Biology (S.-K.L., S.-Y.N.) and Hormone Research Center (J.H.C., Y.C.L., J.W.L.) Chonnam National University Kwangju 500–757, Korea College of Pharmacy (J.-E.C., B.H.J.) Pusan National University Pusan 609–735, Korea Cancer Genetics Branch (P.S.M.) National Human Genome Research Institute National Institutes of Health Bethesda, Maryland 20892-4470
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
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B (NFB) components p50 and p65, as
demonstrated by the glutathione S-transferase pull-down
assays as well as the yeast two-hybrid tests. In cotransfection of
mammalian cells, ASC-2 potentiated transactivations by SRF, AP-1, and
NFB in a dose-dependent manner, either alone or in conjunction with
SRC-1 and p300. In addition, ASC-2 efficiently relieved the previously
described transrepression between nuclear receptors and either AP-1 or
NFB. Overall, these results suggest that the nuclear receptor
coactivator ASC-2 also mediates transactivations by SRF, AP-1, and
NFB, which may contribute to the putative, ASC-2-mediated
tumorigenesis. |
INTRODUCTION |
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TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
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B (NFB) (5, 6), p53 (7), and serum response
factor (SRF) (8). SRC-1 (9) and its homolog ACTR (10), along
with CBP and p300 (11, 12), were recently shown to contain histone
acetyltransferase activities and associate with yet another histone
acetyltransferase protein p/CAF (13). In contrast, silencing mediator
of retinoid and thyroid hormone receptor (SMRT) (14) and nuclear
receptor corepressor (N-CoR) (15), nuclear receptor
corepressors, form complexes with Sin3 and histone deacetylase proteins
(16, 17). These results are consistent with the notion that acetylation
of histones destabilizes nucleosomes and relieves transcriptional
repression by allowing transcription factors to access to recognition
elements, whereas deacetylation of the histones stabilizes the
repressed state (1, 2).
We have recently isolated a novel transcription coactivator
molecule of nuclear receptors (designated ASC-2) (18). In particular,
microinjection of anti-ASC-2 antibody abrogated the ligand-dependent
transactivation of retinoic acid receptor, and this repression was
fully relieved by coinjection of ASC-2-expression vector, consistent
with an idea that ASC-2 is essential for the nuclear receptor function
in vivo (18). Interestingly, ASC-2 was found to be highly
amplified and overexpressed in colon, breast, and lung cancers (18),
although it was not clear whether the altered expression of ASC-2
directly contributed to the development of cancers. Based on the
interactions with multifunctional transcription integrators SRC-1 and
CBP/p300 (1, 2), ASC-2 was suspected to mediate transactivations by
transcription factors other than nuclear receptors. In this regard, it
was interesting to note that high levels of the ASC-2 expression in
various human breast cancer cell lines were not strictly correlated
with the estrogen receptor-
(ER) positivity (18), an important
criterion in breast and ovarian cancers. Thus, if the altered
expression of ASC-2 plays any role in tumorigenesis, it is likely to
involve transcription factors other than ER.
SRF, AP-1, and NFB are known to control a surprisingly diverse set
of genes. However, it is interesting to note that these factors share
at least one common property, i.e. stimulation of cellular
proliferation processes. SRF, along with ternary complex factor (TCF),
binds to and activates the serum response element (SRE), present in the
upstream regulatory sequences of myogenic genes as well as a number of
immediate early genes, including c-fos, which in turn
activate genes critical for cell proliferation (reviewed in Ref. 19).
SRF belongs to the MADS box family of proteins and recognizes a CArG
box in the SRE, whereas TCF does not bind autonomously to the element,
but requires the assistance of SRF to efficiently contact the DNA. The
AP-1 complex, immediate early response genes, consists of a heterodimer
of a Fos family member and a Jun family member (reviewed in Ref. 20).
This complex binds the consensus DNA sequence (TGAGTCA) (termed AP1
sites) found in a variety of promoters. The Fos family contains four
proteins (c-Fos, Fos-B, Fra-1, and Fra-2), whereas the Jun family is
composed of three (c-Jun, Jun-B, and Jun-D). Fos and Jun are members of
the basic-leucine zipper (bZIP) family of sequence-specific dimeric
DNA-binding proteins. The C-terminal half of the bZIP domain is
amphipathic, containing a heptad repeat of leucines that is critical
for the dimerization of bZIP proteins. The N-terminal half of the long
bipartite-helix is the basic region that is critical for
sequence-specific DNA binding. Finally, NFB is composed of homo- and
heterodimeric complexes of members of the Rel (NFB) family
of polypeptides (reviewed in Ref. 21). In vertebrates, this family
comprises p50, p65 (RelA), c-rel, p52, and RelB. These proteins share a
300-amino acid region, known as the Rel homology domain, which binds to
DNA and mediates homo- and heterodimerization. This domain is also a
target of the IB inhibitors, which include IB, IBß,
IB
, Bcl-3, p105, and p100. In the majority of cells, NFB
exists in an inactive form in the cytoplasm, bound to the inhibitory
IB proteins. Treatment of cells with various inducers results in the
degradation of IB proteins. The bound NFB is released and
translocates to the nucleus, where it activates appropriate target
genes. Interestingly, several lines of evidence suggested that
constitutive activation of NFB contribute to the malignant phenotype
of tumor cells. A naturally occurring splice variant of RelA was shown
to transform Rat-1 cells (22), whereas antisense oligonucleotides to
RelA were shown to inhibit proliferation and tumorigenicity of several
tumor cell lines, including the human breast cancer cell lines MCF7 and
T47D (23). In addition, activation of NFB through the disruption of
IB regulation was shown to result in malignant transformation
(24).
Herein, we report the identification of SRF, AP-1, and NFB as new
target molecules of ASC-2, in which ASC-2 directly interacts with these
factors. In cotransfections, ASC-2 potentiated their transactivations
in a dose-dependent manner and appeared to be involved with the
previously characterized transrepression between nuclear receptors and
either AP-1 (25) or NFB (26, 27). These results indicate that ASC-2
may directly regulate the cellular proliferation or tumorigenesis
processes in vivo, by acting as a novel coactivator molecule
of these mitogenic transcription factors.
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RESULTS |
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TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
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) was used as bait. Consistent with the
notion that ASC-2 is a multifunctional transcription integrator
molecule, we have isolated a series of different transcription factors
and cofactors, identical or homologous to the previously characterized
factors (our unpublished results). Among these, two independent
isolates encoded the C-terminal region of SRF (i.e. the SRF
residues 203–504, designated SRF
N), as shown in Fig. 2A. This interaction was confirmed in the
in vitro glutathione S-transferase (GST)
pull-down assays. GST alone and GST-fusions to ASC2–4, ASC2–4.5, and
SRF were expressed, purified, and tested for interaction with in
vitro translated luciferase, SRF, and ASC-2. As shown in Fig. 2B, the radiolabeled SRF readily interacted with GST-ASC2–4 (the ASC-2
residues 1172–1729) and GST-ASC2–4.5 (the ASC-2 residues 1429–2063),
but not with GST alone. Similarly, the radiolabeled ASC-2 interacted
with GST-SRF, but not with GST alone. In contrast, the radiolabeled
luciferase bound neither of the GST proteins, as expected (results not
shown). We have also examined whether the endogenous ASC-2 can bind to
SRF in vitro. As shown in Fig. 2C, GST-SRF but not GST alone
retained the endogenous ASC-2 from HeLa nuclear extracts, as revealed
in Western analysis with the previously described specific monoclonal
antibody against ASC-2 (18). As a positive control, GST fusion to
thyroid hormone receptor (TR) was shown to retain the endogenous ASC-2
from HeLa nuclear extracts in a T3-dependent
manner. From these results, we concluded that ASC-2 specifically binds
to SRF.
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). In the yeast two-hybrid
tests, coexpression of a transactivation domain B42 (28) fusion to
the full-length SRF (i.e. B42-SRF) further stimulated
the LexA-ASC2–4 (the ASC-2 residues 1172–1729), LexA-ASC2–4.5 (the
ASC-2 residues 1429–2063), and LexA-ASC2–5 (the ASC-2 residues
1559–2063)-mediated LacZ expressions. However, coexpression
of B42-SRF did not affect the LexA-ASC2–1 (the ASC-2 residues 1–557),
LexA-ASC2–2 (the ASC-2 residues 391-1057), and LexA-ASC2–3 (the ASC-2
residues 586-1310), and LexA-ASC2–3.5 (the ASC-2 residues
929-1511)-mediated LacZ expressions (Fig. 3A). LexA fusions
to ASC2–1 and ASC2–2 showed autonomous transactivation function, as
previously noted (18). In addition, transactivation mediated by LexA
fusions to ASC2–4a (the ASC-2 residues 1429–1729) and ASC2–4b (the
ASC-2 residues 1559–1729) but not ASC2–4c (the ASC-2 residues
1172–1511) was enhanced by coexpression of B42 fusions to the
full-length SRF (Fig. 3A). Similar
results were also obtained with a B42 fusion to the SRF residues
203–504 (i.e. SRFN). Consistent with these results, B42
fusions to ASC2–4.5, ASC2–4a, and ASC2–4b but not ASC2–4c
stimulated the LexA-SRF and LexA-SRFN-mediated transactivation (Fig. 3B). From these results, we concluded that the SRF transactivation
domain interacts with a region containing the ASC-2 residues 1559–1729
(as summarized in Fig. 1).
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). Increasing
amounts of cotransfected ASC-2 enhanced the reporter gene expressions
in an ASC-2 dose-dependent manner, with cotransfection of 100 ng of
ASC-2 increasing the fold activation approximately 3-fold (Fig. 4A). As
previously reported (8, 30), cotransfected p300 or SRC-1 also had
stimulatory effects on the reporter gene expressions. Consistent with
an idea that CBP/p300 and SRC-1 functionally cooperate with ASC-2,
coexpression of p300 or SRC-1 further increased the reporter gene
expressions above the levels observed with ASC-2 alone (Fig. 4A). In
contrast, cotransfection of ASC-2 did not affect the LacZ
reporter expression of the transfection indicator construct
pRSV-ß-gal either in the presence or absence of serum shock (results
not shown). Similar results were also obtained with a reporter
construct driven by the previously described SRE-containing, natural
c-fos promoter (31) (Fig. 4B). From these results, we
concluded that ASC-2 is a bona fide transcription
coactivator molecule of SRF.
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BB
components p50 and p65 were expressed, purified, and tested for
interaction with in vitro translated ASC-2. As shown in Fig. 5A, the radiolabeled ASC-2 interacted
with all of these GST fusion proteins except GST alone. In contrast,
the radiolabeled SRC-1 bound to GST fusions to c-Jun, c-Fos, and p50
but not p65, as we have previously reported (4, 5). These interactions
were further confirmed in yeast. Coexpression of B42 fusions to c-Jun
and c-Fos stimulated transactivation by LexA-ASC2–2 but not LexA
fusions to ASC2–3, ASC2–3.5, and ASC2–4.5 (Fig. 5B and results not
shown). These results strongly suggest that interactions with c-Jun and
c-Fos are likely to involve the ASC-2 residues 391–585, although this
prediction has yet to be independently confirmed. Coexpression of
B42-p50 stimulated transactivation by LexA fusions to ASC2–2, ASC2–3,
and ASC2–3.5 but not ASC2–4.5, suggesting that the p50 interactions
involve either the ASC-2 residues 929-1057 or multiple regions
throughout the ASC-2 residues 391-1429. Finally, coexpression of
B42-p65N (i.e. the p65 residues 353–550), which
encompasses the p65 transactivation domain, stimulated transactivation
by LexA-ASC2–2 but not LexA-ASC2–3.5 and LexA-ASC2–4.5, suggesting
that the p65 interactions involve the ASC-2 residues 391–929. In
contrast, B42-p65C (i.e. the p65 residues 1–323) did not
show any interactions (Fig. 5B). Overall, these results indicate that
specific subregions of ASC-2 are differentially recognized by the
AP-1/NFB components c-Jun, c-Fos, p50, and p65, as summarized in
Fig. 1.
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B) and
(B)4-interleukin-2 (IL-2)-LUC (Fig. 6C), which
consist of a minimal promoter from the thymidine kinase gene and four
upstream consensus AP-1 sites (4) and a minimal promoter from the
interleukin-2 gene and four upstream B sites from the IL-6 gene (5),
respectively. These reporter constructs were previously characterized
to efficiently mediate the AP-1 and NFB-dependent transactivations,
respectively, in various cell types. Increasing amounts of
cotransfected ASC-2 enhanced the reporter gene expressions in an ASC-2
dose-dependent manner. As previously noted (2, 4, 5), cotransfected
SRC-1 or p300 also had stimulatory effects on these reporter gene
expressions. Consistent with an idea that CBP/p300 and SRC-1
functionally cooperate with ASC-2, coexpression of p300 or SRC-1
further increased the reporter gene expressions above the levels
observed with ASC-2 alone (Fig. 6, A and C). ASC-2 also coactivated the
12-O-tetradecanoylphorbol-13 acetate (TPA)- or tumor
necrosis factor- (TNF)-induced level of transactivations, whereas
cotransfection of ASC-2 did not affect the LacZ reporter
expression of the transfection indicator construct pRSV-ß-gal either
in the presence or absence of TPA or TNF (results not shown). To
investigate the function of ASC-2 in vivo, the
microinjection technique (32) was further used, in which the
LacZ reporter gene was placed under the control of an SV40
minimal promoter containing TPA-responsive AP-1 sites. Remarkably,
microinjection of anti-ASC-2 IgG significantly prevented TPA from
activating this TPA-dependent transcription unit (Fig. 6B) but had no
effect on a promoter under the control of the cytomegalovirus promoter
(results not shown). The percentage of cells that expressed the
LacZ reporter (i.e. blue cells) was not
significant among cells microinjected with control IgG in the absence
of TPA but increased to approximately 45% in the presence of TPA.
However, only approximately 10% of cells turned blue even in the
presence of TPA, when microinjected with anti-ASC-2 IgG (Fig. 6B). This
ASC-2-mediated repression of the TPA response was fully relieved by
coinjected ASC-2-expression vector but not by pcDNA3 (Fig. 6B). Taken
together with the transient transfection data (Fig. 6A), we concluded
that ASC-2 is a molecule pivotal for the function of AP-1 in
vivo. These results, along with the results with SRF (Fig. 4),
NFB (Fig. 6B), and nuclear receptors (18), strongly suggest that
ASC-2 is a multifunctional transcription integrator molecule, like
CBP/p300 and SRC-1.
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BB, which was
suggested to be due to an interaction among these factors that results
in mutual loss of DNA-binding activity (25, 26, 27). More recently,
competition for common transcription coactivators such as CBP/p300 and
SRC-1 was also proposed to be responsible for this mutual antagonism
(4, 33). ASC-2 shows similar effects. Coexpression of ASC-2 enhanced
the T3-dependent transactivation by TR in a
dose-dependent manner (Fig. 7A). As
previously noted (4, 5, 27), however, the
T3-dependent transactivation by TR was repressed
by coexpression of c-Fos or p65 (Fig. 7B), whereas liganded TR
efficiently repressed transactivation of both AP-1 and
NFB-responsive reporter constructs (Fig. 7, C and D). These
inhibitory effects were largely relieved upon addition of increasing
amounts of ASC-2. These results strongly indicate that ASC-2 is
directly involved with the transrepressions between nuclear receptors
and either AP-1 or NFB.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
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), as ASC-2-interacting proteins from the yeast two-hybrid
screening (our unpublished results). Second, ASC-2 was shown to
stimulate transactivations by SRF (Fig. 4), AP-1, and NFB (Fig. 6),
likely through specific interactions with these factors (as summarized
in Fig. 1). Third, ASC-2 appeared to be involved with the previously
defined transrepression between nuclear receptors and either AP-1 or
NFB (Fig. 7). This ASC-2-mediated reversal of the transrepression
between TR and AP-1/NFB (Fig. 7) suggests that a limiting amount of
ASC-2 is competitively recruited by these transcription factors.
However, it is also possible that ASC-2 may titrate out a putative,
secondary factor, which links TR to AP-1/NFB and is required for the
transrepression. Alternatively, the exogenously supplied ASC-2 could be
blocking the protein-protein interactions of TR with AP-1/NFB
(i.e. AP-1 and NFB may directly compete with nuclear
receptors to recruit ASC-2). Consistent with this idea, we noticed that
the c-Jun/c-Fos, p65, and p50-interaction domains of ASC-2 are
clustered around the previously defined receptor interaction domain (as
summarized in Fig. 1). Finally, it’s interesting to note that the
ASC-2 interaction domains of SRF (Fig. 2) and p65 (Fig. 5B) overlap
with their previously defined autonomous transactivation domains
(i.e. the N-terminal region of SRF and the C-terminal region
of p65) (20, 21).
Considering the fact that ASC-2 is highly amplified in human cancers
(18), it’s particularly interesting to note that these newly
identified target proteins of ASC-2 are mitogenic transcription
factors. Recently, AIB1, an SRC-1 family member, was identified as a
gene amplified and overexpressed in breast and ovarian cancers (34).
SRC-1 and its family members were also shown to serve as a novel
transcription coactivator molecule of AP-1 (4), NFB (5, 6), and SRF
(8). Interestingly, ASC-2 maps to 20q11, substantially centromeric to
AIB1 (which maps to 20q12) (35), demonstrating that two distinct
coactivator molecules of nuclear receptors can be coamplified in cancer
cells. Such a co-selection process may favor genes that impinge on the
same cellular processes and result in significant effects on
transcriptional regulation within tumor cells. In particular,
overexpression of these multifunctional integrator molecules may
provide a selective advantage for tumor growth. Thus, it remains to be
determined whether these mitogenic factors (i.e SRF, NFB,
and AP-1) are indeed targeted by increased levels of these coactivator
proteins in vivo to sustain tumor growth. However, it is
interesting to note that the inhibitory effects of the AP-1 and NFB
transactivations by T3 or retinoids can be
significantly attenuated when ASC-2 is overexpressed (Fig. 7 and
results not shown). These results raise an interesting possibility that
overexpressed ASC-2 may contribute to the induction of retinoid
resistance in certain human cancers. In breast cancer cells, both
overexpression of c-Jun and decreased expression of retinoid receptors
were previously shown to result in such retinoid resistance (36, 37).
Our recent unpublished data indicate that ASC-2 forms a distinct
steady-state coactivator complex in vivo and
functionally communicates with other coactivator complexes such as
CBP/p300/SRC-1 (38) and ASC-1 (39). The ASC-2 complex was different
from the ASC-1, CBP/p300, and SRC-1-complexes (38, 39) when eluted from
a sizing column. Interestingly, this endogenous ASC-2 complex was
readily retained by GST fusions to SRF, TR, and p50 (Fig. 2C and
results not shown). In particular, the TR interactions were strictly
T3-dependent, as expected (18). Similar to the
previously shown results with nuclear receptors (18), microinjection of
ASC-2 antibody effectively disrupted the AP-1 transactivation by TPA
(Fig. 6B), suggesting that this ASC-2 complex is essential for at least
two classes of transcription factors in vivo,
i.e. AP-1 and nuclear receptors. Currently, one of our major
focuses is to elucidate the molecular mechanisms by which the ASC-2
complex functions and its activity is regulated. First, we are
biochemically dissecting the components of the ASC-2 complex. Second,
we have recently found that expression of ASC-2 mRNA is up-regulated in
certain cells by various cytokines and growth factors, including IL-1
and epidermal growth factor (EGF), activating signals for NFB and
AP-1/SRF, respectively (our unpublished results). Similarly,
transcripts of the SRC-1 family member RAC3 (40) and the nuclear
receptor corepressor molecule SMRT (14) were recently shown to be
directly up-regulated by retinoids (41, 42). Expression of PGC-1, a
thermogenic tissue-specific coactivator of nuclear receptors, was also
shown to be temporally regulated (43). To understand this up-regulation
of ASC-2, we have recently isolated its full-promoter from a human
genomic library, which contains a series of interesting regulatory
sites, including AP-1 sites (results not shown). Finally, ASC-2
contains a numerous number of putative phosphorylation sites (18) and,
thus, the possible regulation of its inherent activity through various
signal transduction pathways is being examined. Recently, this notion
has been confirmed with CBP, in which a calcium flux was shown to
function as an activating signal for its stimulatory transcriptional
activity (44).
In conclusion, we identified three mitogenic transcription factors
(i.e. SRF, AP-1, and NFB) as novel targets for ASC-2,
which may contribute to the putative, ASC-2-mediated tumorigenesis. We
have also shown that ASC-2 is a multifunctional transcription
integrator molecule, like SRC-1 (1, 3, 4, 5, 6, 7, 8) and CBP/p300 (2). Thus,
further characterization of ASC-2 may provide important insights into
the tumorigenesis processes as well as the molecular mechanisms by
which multiple transcription factors are coordinately regulated within
the cell.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
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N (i.e. the p65
residues 353–550) and p65C (i.e. the p65 residues
1–323) were cloned into EcoRI and
XhoI/SalI restriction sites of pEG202PL and
pJG4–5 (28), respectively. For GST fusion vectors, PCR fragments
encoding ASC2–4 and ASC2–4.5 were cloned into EcoRI and
XhoI restriction site of pGEX4T (Pharmacia Biotech, Piscataway, NJ). The AP-1-SV40-ß-GAL reporter
construct was a gift from Dr. Dave Rose (University of California, San
Diego, CA). GST fusion vectors encoding SRF, TR, c-Jun, c-Fos, p50, and
p65 as well as the mammalian expression vectors for SRF, ASC-2, p300,
SRC-1, c-Fos, p65, and TR, along with the transfection indicator
construct pRSV-ß-gal and reporter constructs
SRE-c-fos-LUC, c-fos-LUC, T3RE-TK-LUC,
(AP-1)4-TK-LUC, and
(B)4-IL-2-LUC, were as previously described
(4, 5, 7, 8, 18, 27, 29, 31, 39).
The Yeast Two-Hybrid Screening and Yeast ß-Galactosidase
Assay
The LexA-ASC2–4 (Fig. 1) was used as a bait to screen a mouse
liver cDNA library in pJG4–5 (28) for ASC-2-interacting proteins, and
the screening was executed essentially as previously described (45).
The yeast ß-galactosidase assay was done as described (28). For each
experiment, at least three independently derived colonies expressing
chimeric proteins were tested.
GST Pull-Down Assays
The GST-fusions or GST alone was expressed in Escherichia
coli, bound to glutathione-Sepharose-4B beads (Pharmacia Biotech), and incubated with labeled proteins expressed by
in vitro translation by using the TNT-coupled
transcription-translation system, with conditions as described by the
manufacturer (Promega Corp., Madison, WI). Specifically
bound proteins were eluted from beads with 40 mM
reduced glutathione in 50 mM Tris (pH 8.0) and
analyzed by SDS-PAGE and autoradiography as described (28).
Cell Culture and Transfections
HeLa, NIH3T3, and CV-1 cells were grown in 24-well plates with
medium supplemented with 10% FCS for 24 h and transfected with
100 ng of LacZ expression vector pRSV-ß-gal and 100 ng of
an indicated reporter gene, along with indicated amounts of various
mammalian expression vectors. Total amounts of expression vectors were
kept constant by adding pcDNA3. Transfections and luciferase assays
were done as described (4, 5, 8), and the results were normalized to
the LacZ expression. Similar results were obtained in more
than two similar experiments.
Single-Cell Microinjection Assay
Rat-1 fibroblast cells, made quiescent by incubating in
serum-free medium for 24 h, were microinjected with either
preimmune IgG or the affinity-purified anti-ASC-2 IgG along with
AP-1-SV40-ß-GAL reporter construct (25 µg/ml). About 1 h after
injection, cells were stimulated, where indicated, with 0.1
µM TPA. After 4 h incubation, cells were fixed and
stained to detect injected IgG by using fluorescein
isothiocyanate (FITC)-conjugated antibodies and examined for
ß-galactosidase expression as previously described (32).
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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This work was supported by a grant from the National Creative Research Initiatives Program from the Korean Ministry of Science and Technology, Republic of Korea. B.H.J was supported by a grant from the Korean Ministry of Public Health (HMP-98-B-3–0022).
Received for publication November 16, 1999. Revision received January 24, 2000. Accepted for publication February 24, 2000.
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 A. Murakami, T. Shigemori, and H. Ohigashi Zingiberaceous and Citrus Constituents, 1'-Acetoxychavicol Acetate, Zerumbone, Auraptene, and Nobiletin, Suppress Lipopolysaccharide-Induced Cyclooxygenase-2 Expression in RAW264.7 Murine Macrophages through Different Modes of Action J. Nutr., December 1, 2005; 135(12): 2987S - 2992S. [Abstract] [Full Text] [PDF]
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E. Choi, S. Lee, S.-Y. Yeom, G. H. Kim, J. W. Lee, and S.-W. Kim Characterization of Activating Signal Cointegrator-2 as a Novel Transcriptional Coactivator of the Xenobiotic Nuclear Receptor Constitutive Androstane Receptor Mol. Endocrinol., July 1, 2005; 19(7): 1711 - 1719. [Abstract] [Full Text] [PDF]
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 M. A. Mahajan and H. H. Samuels Nuclear Hormone Receptor Coregulator: Role in Hormone Action, Metabolism, Growth, and Development Endocr. Rev., June 1, 2005; 26(4): 583 - 597. [Abstract] [Full Text] [PDF]
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I. Quelo, C. Gauthier, G. E. Hannigan, S. Dedhar, and R. St-Arnaud Integrin-linked Kinase Regulates the Nuclear Entry of the c-Jun Coactivator {alpha}-NAC and Its Coactivation Potency J. Biol. Chem., October 15, 2004; 279(42): 43893 - 43899. [Abstract] [Full Text] [PDF]
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 H. Zhang, S.-Q. Kuang, L. Liao, S. Zhou, and J. Xu Haploid Inactivation of the Amplified-in-Breast Cancer 3 Coactivator Reduces the Inhibitory Effect of Peroxisome Proliferator-Activated Receptor {gamma} and Retinoid X Receptor on Cell Proliferation and Accelerates Polyoma Middle-T Antigen-Induced Mammary Tumorigenesis in Mice Cancer Res., October 1, 2004; 64(19): 7169 - 7177. [Abstract] [Full Text] [PDF]
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N. Yin, D. Wang, H. Zhang, X. Yi, X. Sun, B. Shi, H. Wu, G. Wu, X. Wang, and Y. Shang Molecular Mechanisms Involved in the Growth Stimulation of Breast Cancer Cells by Leptin Cancer Res., August 15, 2004; 64(16): 5870 - 5875. [Abstract] [Full Text] [PDF]
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S. Hong, H. M. Choi, M. J. Park, Y. H. Kim, Y. H. Choi, H. H. Kim, Y. H. Choi, and J. Cheong Activation and Interaction of ATF2 with the Coactivator ASC-2 Are Responsive for Granulocytic Differentiation by Retinoic Acid J. Biol. Chem., April 23, 2004; 279(17): 16996 - 17003. [Abstract] [Full Text] [PDF]
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 M. Oukka, M. N. Wein, and L. H. Glimcher Schnurri-3 (KRC) Interacts with c-Jun to Regulate the IL-2 Gene in T Cells J. Exp. Med., January 5, 2004; 199(1): 15 - 24. [Abstract] [Full Text] [PDF]
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C. M. Litterst, S. Kliem, D. Marilley, and E. Pfitzner NCoA-1/SRC-1 Is an Essential Coactivator of STAT5 That Binds to the FDL Motif in the {alpha}-Helical Region of the STAT5 Transactivation Domain J. Biol. Chem., November 14, 2003; 278(46): 45340 - 45351. [Abstract] [Full Text] [PDF]
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 S.-W. Kim, K. Park, E. Kwak, E. Choi, S. Lee, J. Ham, H. Kang, J. M. Kim, S. Y. Hwang, Y.-Y. Kong, et al. Activating Signal Cointegrator 2 Required for Liver Lipid Metabolism Mediated by Liver X Receptors in Mice Mol. Cell. Biol., May 15, 2003; 23(10): 3583 - 3592. [Abstract] [Full Text] [PDF]
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 H. Zhang, L. Liao, S.-Q. Kuang, and J. Xu Spatial Distribution of the Messenger Ribonucleic Acid and Protein of the Nuclear Receptor Coactivator, Amplified in Breast Cancer-3, in Mice Endocrinology, April 1, 2003; 144(4): 1435 - 1443. [Abstract] [Full Text] [PDF]
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S. V. Komarova, M. F. Pilkington, A. F. Weidema, S. J. Dixon, and S. M. Sims RANK Ligand-induced Elevation of Cytosolic Ca2+ Accelerates Nuclear Translocation of Nuclear Factor kappa B in Osteoclasts J. Biol. Chem., February 28, 2003; 278(10): 8286 - 8293. [Abstract] [Full Text] [PDF]
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Y.-H. Goo, Y. C. Sohn, D.-H. Kim, S.-W. Kim, M.-J. Kang, D.-J. Jung, E. Kwak, N. A. Barlev, S. L. Berger, V. T. Chow, et al. Activating Signal Cointegrator 2 Belongs to a Novel Steady-State Complex That Contains a Subset of Trithorax Group Proteins Mol. Cell. Biol., January 1, 2003; 23(1): 140 - 149. [Abstract] [Full Text]
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S.-Q. Kuang, L. Liao, H. Zhang, F. A. Pereira, Y. Yuan, F. J. DeMayo, L. Ko, and J. Xu Deletion of the Cancer-amplified Coactivator AIB3 Results in Defective Placentation and Embryonic Lethality J. Biol. Chem., November 15, 2002; 277(47): 45356 - 45360. [Abstract] [Full Text] [PDF]
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D.-J. Jung, H.-S. Sung, Y.-W. Goo, H. M. Lee, O. K. Park, S.-Y. Jung, J. Lim, H.-J. Kim, S.-K. Lee, T. S. Kim, et al. Novel Transcription Coactivator Complex Containing Activating Signal Cointegrator 1 Mol. Cell. Biol., July 15, 2002; 22(14): 5203 - 5211. [Abstract] [Full Text] [PDF]
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D. A. Tice, I. Soloviev, and P. Polakis Activation of the Wnt Pathway Interferes with Serum Response Element-driven Transcription of Immediate Early Genes J. Biol. Chem., February 15, 2002; 277(8): 6118 - 6123. [Abstract] [Full Text] [PDF]
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Y. C. Sohn, E. Kwak, Y. Na, J. W. Lee, and S.-K. Lee Silencing Mediator of Retinoid and Thyroid Hormone Receptors and Activating Signal Cointegrator-2 as Transcriptional Coregulators of the Orphan Nuclear Receptor Nur77 J. Biol. Chem., November 16, 2001; 276(47): 43734 - 43739. [Abstract] [Full Text] [PDF]
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S.-K. Lee, S.-Y. Jung, Y.-S. Kim, S.-Y. Na, Y. C. Lee, and J. W. Lee Two Distinct Nuclear Receptor-Interaction Domains and CREB-Binding Protein-Dependent Transactivation Function of Activating Signal Cointegrator-2 Mol. Endocrinol., February 1, 2001; 15(2): 241 - 254. [Abstract] [Full Text]
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L. J. Nissen, J.-C. Gelly, and R. A. Hipskind Induction-independent Recruitment of CREB-binding Protein to the c-fos Serum Response Element through Interactions between the Bromodomain and Elk-1 J. Biol. Chem., February 9, 2001; 276(7): 5213 - 5221. [Abstract] [Full Text] [PDF]
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M. K. Jang, Y. H. Goo, Y. C. Sohn, Y. S. Kim, S.-K. Lee, H. Kang, J. Cheong, and J. W. Lee Ca2+/Calmodulin-dependent Protein Kinase IV Stimulates Nuclear Factor-kappa B Transactivation via Phosphorylation of the p65 Subunit J. Biol. Chem., June 1, 2001; 276(23): 20005 - 20010. [Abstract] [Full Text] [PDF]
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N. V. Kumar and L. R. Bernstein Ten ERK-related Proteins in Three Distinct Classes Associate with AP-1 Proteins and/or AP-1 DNA J. Biol. Chem., August 17, 2001; 276(34): 32362 - 32372. [Abstract] [Full Text] [PDF]
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D.-J. Jung, S.-Y. Na, D. S. Na, and J. W. Lee Molecular Cloning and Characterization of CAPER, a Novel Coactivator of Activating Protein-1 and Estrogen Receptors J. Biol. Chem., January 4, 2002; 277(2): 1229 - 1234. [Abstract] [Full Text] [PDF]
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