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Query: EC:2.7.11.1 (
protein kinase
)
81,284
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The cytokine transforming growth factor beta (TGF-beta) plays an important role in preventing tumor formation by blocking cell cycle progression. Accordingly, many cancers demonstrate mutations in TGF-beta signaling components or enhanced expression of inhibitors of the TGF-beta pathway such as Smad7. In this report we show that the oncoprotein HER2/Neu is able to collaborate with the ETS transcription factor ER81 to activate Smad7 transcription in breast, endometrial, and ovarian cancer cell lines. ER81 binds to two ETS sites within the Smad7 promoter, and mutation of one of these ETS sites greatly decreases Smad7 induction by HER2/Neu and ER81. Furthermore, we show that Smad7 activation involves the processing of signals from HER2/Neu to ER81 via the ERK mitogen-activated protein kinase pathway. Thus, we have uncovered a novel mechanism by which oncogenic HER2/Neu, in collaboration with ER81, can induce carcinogenesis through Smad7 up-regulation. Moreover, we show that
TAK1
, a TGF-beta-activated
protein kinase
, stimulates ER81 via the p38 mitogen-activated protein kinase pathway and thereby induces the Smad7 promoter. This suggests that attenuation of TGF-beta signaling by activating Smad7 transcription may proceed not only through TGF-beta receptor-regulated Smad proteins but also through an independent pathway involving ER81 and
TAK1
.
...
PMID:HER2/Neu- and TAK1-mediated up-regulation of the transforming growth factor beta inhibitor Smad7 via the ETS protein ER81. 1294 87
We have identified a new binding partner of the TGFbeta (transforming growth factor-beta)-activated
protein kinase
(
TAK1
), termed TAB3 (
TAK1
-binding protein-3), which shares 48% amino acid sequence identity with TAB2. Our results indicate that two distinct
TAK1
complexes are present in cells. One comprises
TAK1
complexed with TAB1 and TAB2, and the other
TAK1
complexed with TAB1 and TAB3. Both complexes are activated in response to tumour necrosis factor-alpha or interleukin-1 in human epithelial KB cells or bacterial lipopolysaccharide in RAW264.7 macrophages, and are subject to feedback control by stress-activated protein kinase 2a (SAPK2a; also called p38alpha). The electrophoretic mobility of TAB2 and TAB3 decreases in response to these agonists or osmotic shock, and is reversed by treatment with protein phosphatase-1. The decrease in mobility of TAB3 is prevented if the cells are incubated with SB 203580 before stimulation, but treatment with SB 203580 produces forms of TAB2 with a mobility intermediate between that observed for TAB2 in unstimulated and stimulated cells. Similar results were obtained in embryonic fibroblasts from mice deficient in SAPK2a/p38alpha. Our results indicate that TAB3 is phosphorylated via the SAPK2a/p38alpha pathway, whereas TAB2 is phosphorylated at two or more sites by both an SAPK2a/p38alpha-dependent and an SB 203580-independent kinase. The SAPK2a/p38alpha-mediated phosphorylation of TAB2 and TAB3 may contribute to the SAPK2a/p38alpha-mediated feedback control of
TAK1
activity that also involves the phosphorylation of TAB1. We also show that the agonist-induced activation of
TAK1
complexes requires the phosphorylation of the
TAK1
catalytic subunit at a serine/threonine residue(s).
...
PMID:TAB3, a new binding partner of the protein kinase TAK1. 1467 75
The c-myb proto-oncogene product (c-Myb) regulates both the proliferation and apoptosis of hematopoietic cells by inducing the transcription of a group of target genes. However, the biologically relevant molecular mechanisms that regulate c-Myb activity remain unclear. Here we report that c-Myb protein is phosphorylated and degraded by Wnt-1 signal via the pathway involving
TAK1
(TGF-beta-activated kinase),
HIPK2
(homeodomain-interacting protein kinase 2), and NLK (Nemo-like kinase). Wnt-1 signal causes the nuclear entry of
TAK1
, which then activates
HIPK2
and the mitogen-activated protein (MAP) kinase-like kinase NLK. NLK binds directly to c-Myb together with
HIPK2
, which results in the phosphorylation of c-Myb at multiple sites, followed by its ubiquitination and proteasome-dependent degradation. Furthermore, overexpression of NLK in M1 cells abrogates the ability of c-Myb to maintain the undifferentiated state of these cells. The down-regulation of Myb by Wnt-1 signal may play an important role in a variety of developmental steps.
...
PMID:Wnt-1 signal induces phosphorylation and degradation of c-Myb protein via TAK1, HIPK2, and NLK. 1508 31
The CARD domain protein BCL10 and paracaspase MALT1 are essential for the activation of IkappaB kinase (IKK) and NF-kappaB in response to T cell receptor (TCR) stimulation. Here we present evidence that TRAF6 ubiquitin ligase and
TAK1
protein kinase
mediate IKK activation by BCL10 and MALT1. RNAi-mediated silencing of MALT1,
TAK1
, TRAF6, and TRAF2 suppressed TCR-dependent IKK activation and interleukin-2 production in T cells. Furthermore, we have reconstituted the pathway from BCL10 to IKK activation in vitro with purified proteins of MALT1, TRAF6,
TAK1
, and ubiquitination enzymes including Ubc13/Uev1A. We find that a small fraction of BCL10 and MALT1 proteins form high molecular weight oligomers. Strikingly, only these oligomeric forms of BCL10 and MALT1 can activate IKK in vitro. The MALT1 oligomers bind to TRAF6, induce TRAF6 oligomerization, and activate the ligase activity of TRAF6 to polyubiquitinate NEMO. These results reveal an oligomerization --> ubiquitination --> phosphorylation cascade that culminates in NF-kappaB activation in T lymphocytes.
...
PMID:The TRAF6 ubiquitin ligase and TAK1 kinase mediate IKK activation by BCL10 and MALT1 in T lymphocytes. 1512 33
Recently we have shown that the c-myb proto-oncogene product (c-Myb) is degraded in response to Wnt-1 signaling via the pathway involving
TAK1
(transforming growth factor-beta-activated kinase),
HIPK2
(homeodomain-interacting protein kinase 2), and NLK (Nemo-like kinase). NLK and
HIPK2
bind directly to c-Myb, which results in the phosphorylation of c-Myb at multiple sites, followed by its ubiquitination and proteasome-dependent degradation. The v-myb gene carried by avian myeloblastosis virus has a transforming capacity, but the c-myb proto-oncogene does not. Here, we report that two characteristics of v-Myb make it relatively resistant to Wnt-1-induced protein degradation. First,
HIPK2
binds with a lower affinity to the DNA-binding domain of v-Myb than to that of c-Myb. The mutations of three hydrophobic amino acids on the surface of the DNA-binding domain in v-Myb decrease the affinity to
HIPK2
. Second, a loss of multiple NLK phosphorylation sites by truncation of the C-terminal region of c-Myb increases its stability. Among 15 putative NLK phosphorylation sites in mouse c-Myb, the phosphorylation sites in the C-terminal region are more critical than other sites for Wnt-1-induced protein degradation. The relative resistance of v-Myb to Wnt-1-induced degradation may explain, at least in part, the differential transforming capacity of v-Myb versus c-Myb.
...
PMID:Differential sensitivity of v-Myb and c-Myb to Wnt-1-induced protein degradation. 1530 26
The activation of NF-kappaB and IKK requires an upstream kinase complex consisting of
TAK1
and adaptor proteins such as TAB1, TAB2, or TAB3.
TAK1
is in turn activated by TRAF6, a RING domain ubiquitin ligase that facilitates the synthesis of lysine 63-linked polyubiquitin chains. Here we present evidence that TAB2 and TAB3 are receptors that bind preferentially to lysine 63-linked polyubiquitin chains through a highly conserved zinc finger (ZnF) domain. Mutations of the ZnF domain abolish the ability of TAB2 and TAB3 to bind polyubiquitin chains, as well as their ability to activate
TAK1
and IKK. Significantly, replacement of the ZnF domain with a heterologous ubiquitin binding domain restored the ability of TAB2 and TAB3 to activate
TAK1
and IKK. We also show that TAB2 binds to polyubiquitinated RIP following TNFalpha stimulation. These results indicate that polyubiquitin binding domains represent a new class of signaling domains that regulate
protein kinase
activity through a nonproteolytic mechanism.
...
PMID:TAB2 and TAB3 activate the NF-kappaB pathway through binding to polyubiquitin chains. 1532 70
Signaling by TNF-family receptor CD40 involves TRAF-family adaptor proteins, leading to activation of protein kinases that induce NFkappaB-family transcription factors. We report here that mitogen activated
protein kinase
kinase kinase-8 (MAP3K8), Tpl2/COT1, is recruited to the CD40 complex via a mechanism dependent on TRAF-binding sites in CD40. Tpl2/COT1 was shown to participate in CD40 signaling based on the ability of a catalytically inactive mutant to suppress CD40-mediated IkappaB kinase activation and induction of NFkappaB-responsive promoters, without affecting signaling by TNF. Tpl2 (-/-) fibroblasts were also deficient in CD40 but not TNF signaling, further supporting a unique role for Tpl2 in CD40 signaling. Experiments using dominant-negative Tpl2 suggest this kinase functions distal to TRAFs but proximal to the
TAK1
/TAB1 signaling complex, within the IKK/NFkappaB activation pathway. These results indicate a distinction between TNF Receptor family members CD40 and TNFR1 in their utilization of MAP3Ks, and demonstrate TRAF-dependence of Tpl2 association with the CD40 receptor complex.
...
PMID:TRAF-dependent association of protein kinase Tpl2/COT1 (MAP3K8) with CD40. 1567 Jul 70
The inflammatory response is characterized by the induction (or repression) of hundreds of genes. The activity of many of these genes is controlled by MAPKs and the IkappaB kinase-NFkappaB pathway. To reveal the effects of blocking these pathways simultaneously, fibroblasts were infected with retroviruses encoding TAK1K63W, an inactive mutant of the
protein kinase
TAK1
. Expression of this protein inhibited tumor necrosis factor (TNF)-induced activation of NFkappaB, JNK, and p38 MAPK and sensitized the cells to TNF-induced apoptosis. 23 different microarray experiments were used to analyze the expression of >7000 genes in these cells. We identified 518 genes that were regulated by TNF in both TAK1K63W-expressing cells and control cells, 37 genes induced by TNF only when TAK1K63W was present, and 48 TNF-induced genes that were suppressed by TAK1K63W. The TNF-inducible genes that were most strongly suppressed by TAK1K63W, ccl2, ccl7, ccl5, cxcl1, cxcl5, cxcl10, saa3, and slpi also had much lower basal levels of expression, indicating that
TAK1
also played a role in their normal expression. Chromatin immunoprecipitation studies on four of these genes suggested that inactivation of
TAK1
activity led to direct suppression of expression at the transcriptional level because of impaired recruitment of RNA polymerase II to their promoters. ccl2 induction by TNF or interleukin-1 was also suppressed in cells that expressed
TAK1
antisense RNA or that were genetically deficient in JNK1/2 or p65 NFkappaB. These data suggest that regulation of the expression of a selected group of inflammation-related genes is funneled through
TAK1
, making it a potentially useful target for more specific anti-inflammatory drug development.
...
PMID:Simultaneous blockade of NFkappaB, JNK, and p38 MAPK by a kinase-inactive mutant of the protein kinase TAK1 sensitizes cells to apoptosis and affects a distinct spectrum of tumor necrosis factor [corrected] target genes. 1583 94
Mammalian mitogen-activated protein kinase (MAPK) cascades control various cellular events, ranging from cell growth to apoptosis, in response to external stimuli. A conserved docking site, termed DVD, is found in the mammalian MAP kinase kinases (MAPKKs) belonging to the three major subfamilies, namely MEK1, MKK4/7, and MKK3/6. The DVD sites bind to their specific upstream MAP kinase kinase kinases (MAPKKKs), including MTK1 (MEKK4), ASK1,
TAK1
, TAO2, MEKK1, and
Raf-1
. DVD site is a stretch of about 20 amino acids immediately on the C-terminal side of the MAPKK catalytic domain. Mutations in the DVD site strongly inhibited MAPKKs from binding to, and being activated by, their specific MAPKKKs, both in vitro and in vivo. DVD site mutants could not be activated by various external stimuli in vivo. Synthetic DVD oligopeptides inhibited specific MAPKK activation, both in vitro and in vivo, demonstrating the critical importance of the DVD docking in MAPK signaling.
...
PMID:Conserved docking site is essential for activation of mammalian MAP kinase kinases by specific MAP kinase kinase kinases. 1586 72
TAK1
(transforming growth factor-beta-activated kinase-1), a MAP3K with considerable sequence similarity to
Raf-1
and MEKK-1, has been identified as a transforming growth factor-beta/bone morphogenetic protein (BMP)-activated cytosolic component of the MAPK pathways. In this investigation, the molecular interactions between
TAK1
and Smad proteins were characterized as well as their influence on BMP-mediated mesenchymal cell differentiation along the osteogenic/chondrogenic pathway. In co-immunoprecipitations we found an interaction of
TAK1
with all Smads tested, R-Smads Smads1-5, the co-Smad Smad4, and the inhibitory Smads (I-Smad6 and I-Smad7). Smad interaction with
TAK1
takes place through their MH2 domain. This interaction is dependent on the presence of an active kinase domain in
TAK1
.
TAK1
dramatically interferes with R-Smad transactivation in reporter assays and affects subcellular distribution of Smad proteins. Activated
TAK1
also interferes with BMP-dependent osteogenic development in murine mesenchymal progenitor cells (C3H10T 1/2). A potential
TAK1
-mediated apoptosis process could be excluded for these cells. Both synergistic and interfering influences of
TAK1
on BMP-mediated Smad-signaling have been reported previously. We suggest that
TAK1
is a factor that is involved in the fine-tuning of BMP effects during osteogenic development.
...
PMID:Transforming growth factor-beta-activated kinase-1 (TAK1), a MAP3K, interacts with Smad proteins and interferes with osteogenesis in murine mesenchymal progenitors. 1591 26
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