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Query: UNIPROT:P05412 (
c-Jun
)
11,453
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Recent evidence suggests that vasoconstrictive substances, including angiotensin II (
Ang II
), may function as a vascular smooth muscle growth promoting substance and may contribute to vascular hypertrophy in hypertension. Atrial natriuretic polypeptide (ANP) is known to be a physiological antagonist to
Ang II
in blood pressure and fluid homeostasis. Moreover, we have demonstrated that ANP can attenuate
Ang II
's action on vascular hypertrophy. In this study, we investigated the potential molecular mechanisms for the interaction of ANP and
Ang II
on vascular cell growth.
Ang II
dose-dependently induced RNA synthesis in post confluent cultured rat aortic smooth muscle (RASM) cells. ANP (10(-7) M) inhibited the hypertrophic effect of
Ang II
at the concentration of 10(-10) - 10(-8) M) but exerted no effect on the action of higher doses (10(-7) - 10(-6) M) of
Ang II
.
Ang II
(10(9) - 10(-8) M) and a protein kinase C activator, phorbol 12-myristate 13-acetate (PMA, 10(-8) M) rapidly induced c-fos as well as
c-Jun
and Jun-B mRNA expression in RASM cells. ANP (10(-7) M) itself had no apparent effect on the expression of these protooncogenes. Furthermore, ANP did not inhibit the induction of these protooncogenes by
Ang II
or PMA. Paradoxically, ANP (10(-7) M) significantly enhanced c-fos mRNA expression induced by
Ang II
and PMA. However, the chloramphenicol acetyl transferase (CAT) assay using a CAT expression vector containing the AP-1 binding element showed that ANP had no effect on the basal and PMA-stimulated AP-1 activity in transfected RASM cells. We conclude, therefore, that the inhibitory effect of ANP on the growth of vascular smooth muscle cells in vitro does not occur through the regulation of these protooncogene expressions.
...
PMID:Interaction of atrial natriuretic polypeptide and angiotensin II on protooncogene expression and vascular cell growth. 182 53
In GN4 rat liver epithelial cells, angiotensin II (
Ang II
) and other agonists which activate phospholipase C stimulate tyrosine kinase activity in a calcium-dependent, protein kinase C (PKC)-independent manner. Since
Ang II
also produces a proliferative response in these cells, we investigated downstream signaling elements traditionally linked to growth control by tyrosine kinases. First,
Ang II
, like epidermal growth factor (EGF), stimulated AP-1 binding activity in a PKC-independent manner. Because increases in AP-1 can reflect induction of
c-Jun
and c-Fos, we examined the activity of the mitogen-activated protein (MAP) kinase family members Erk-1 and -2 and the c-Jun N-terminal kinase (JNK), which are known to influence
c-Jun
and c-Fos transcription.
Ang II
stimulated MAP kinase (MAPK) activity but only approximately 50% as effectively as EGF; again, these effects were independent of PKC.
Ang II
also produced a 50- to 200-fold activation of JNK in a PKC-independent manner. Unlike its smaller effect on MAPK,
Ang II
was approximately four- to sixfold more potent in activating JNK than EGF was. Although others had reported a lack of calcium ionophore-stimulated JNK activity in lymphocytes and several other cell lines, we examined the role of calcium in GN4 cells. The following results suggest that JNK activation in rat liver epithelial cells is at least partially Ca(2+) dependent: (i) norepinephrine and vasopressin hormones that increase inositol 1,4,5-triphosphate stimulated JNK; (ii) both thapsigargin, a compound that produces an intracellular Ca(2+) signal, and Ca(2+) ionophores stimulated a dramatic increase in JNK activity (up to 200-fold); (iii) extracellular Ca(2+) chelation with ethylene glycol tetraacetic acid (EGTA) inhibited JNK activation by ionophore and intracellular chelation with 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl-ester (BAPTA-AM) partially inhibited JNK activation by
Ang II
or thapsigargin; and (iv) JNK activation by
Ang II
was inhibited by pretreatment of cells with thapsigargin and EGTA, a procedure which depletes intracellular Ca(2+) stores. JNK activation following
Ang II
stimulation did not involve calmodulin; either W-7 nor calmidizolium, in concentrations sufficient to inhibit Ca(2+)/calmodulin-dependent kinase II, blocked JNK activation by
Ang II
. In contrast, genistein, in concentrations sufficient to inhibit Ca(2+)-dependent tyrosine phosphorylation, prevented
Ang II
and thapsigargin-induced JNK activation. In summary, in GN4 rat liver epithelial cells,
Ang II
stimulates JNK via a novel Ca(2+)-dependent pathway. The inhibition by genistein suggest that Ca(2+)-dependent tyrosine phosphorylation may modulate the JNK pathway in a cell type-specific manner, particularly in cells with a readily detectable Ca(2+)-regulated tyrosine kinase.
...
PMID:Angiotensin II stimulates calcium-dependent activation of c-Jun N-terminal kinase. 756 68
Angiotensin II
(Ang-II) receptor engagement activates many immediate early response genes in both vascular smooth muscle cells and cardiomyocytes whether a hyperplastic or hypertrophic response is taking place. Although the signaling pathways stimulated by Ang-II in different cell lines have been widely characterized, the correlation between the generation of different second messengers and specific physiological responses remains relatively unexplored. In this study, we report how in both C2C12 quiescent myoblasts and differentiated myotubes Ang-II significantly stimulates AP1-driven transcription and
c-Jun
.c-Fos heterodimer DNA binding activity. Using a set of different protein kinase inhibitors, we could demonstrate that Ang-II-induced increase in AP1 binding is not mediated by the cAMP-dependent pathway and that both protein kinase C and tyrosine kinases are involved. The observation that in quiescent myoblasts Ang-II increase of AP1 binding and induction of DNA synthesis and, in differentiated myotubes, Ang-II stimulation of protein synthesis are abolished by the cysteine-derivative and glutathione precursor N-acetyl-L-cysteine strongly suggests a role for reactive oxygen intermediates in the intracellular transduction of Ang-II signals for immediate early gene induction, cell proliferation, and hypertrophic responses.
...
PMID:Reactive oxygen intermediates mediate angiotensin II-induced c-Jun.c-Fos heterodimer DNA binding activity and proliferative hypertrophic responses in myogenic cells. 767 90
We investigated the effects of intracerebroventricular injection of angiotensin II on neuronal immediate early gene-encoded protein synthesis in the brain of conscious rats. The expression of seven immediate early gene-encoded transcription factors (c-Fos, FosB,
c-Jun
, JunB, JunD, Krox-20 (Egr-2) and Krox-24 (NGFI-A, Egr-1, Zif/268) was assessed simultaneously.
Angiotensin II
(1, 10, 100 ng) induced a dose-dependent expression of c-Fos and Krox-24 in the subfornical organ, the median preoptic area and in the paraventricular nucleus and supraoptic nucleus of the hypothalamus, regions known to be involved in the central osmoregulatory and neuroendocrine actions of angiotensin II. FosB expression was induced four hours after icv injection of the highest dose of angiotensin II in the median preoptic area and paraventricular nucleus,
c-Jun
expression was restricted to the median preoptic area, subfornical organ and paraventricular nucleus, and JunB was only induced in the median preoptic area and subfornical organ. In these above mentioned regions, JunD exhibited a high basal staining, which was not visibly altered by angiotensin II. Krox-20 was not induced by angiotensin II. Intracerebroventricular injections of isotonic saline did not induce immediate early gene expression in any of the above brain areas. The angiotensin II-AT1 receptor antagonist, losartan, applied intracerebroventricular five minutes prior to angiotensin II, prevented the angiotensin II-induced immediate early gene protein expression. Losartan alone had no effects on immediate early gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Angiotensin II induces a complex activation of transcription factors in the rat brain: expression of Fos, Jun and Krox proteins. 775 10
Increasing evidence suggests that angiotensin II may act as a growth factor for several muscle cell types.
Angiotensin II
stimulation activates many immediate early response genes like c-Fos,
c-Jun
, c-Myc and Egr-1 in both vascular smooth muscle cells and cardiomyocytes, independently of whether a hyperplastic or hypertrophic response is taking place. In this study we report that angiotensin II significantly stimulates AP1-driven transcription in mouse skeletal muscle cells C2C12 stably transfected with a TRE-tk-CAT plasmid in a dose-dependent manner (peak stimulation at 10(-5) M of angiotensin II). Moreover, angiotensin II increases the binding of the AP1 complex to its DNA target in both quiescent C2C12 myoblasts and in differentiated C2C12 myotubes. Most of the TRE-bound complexes in both unstimulated and angiotensin II-treated cells consist of c-jun/c-fos heterodimers. Using a set of different protein kinase inhibitors, including HA1004, H7, tyrphostin, genistein and staurosporine, we could demonstrate that the angiotensin II-induced AP1 binding increase is not mediated by the cAMP-dependent pathway and that protein kinase C and tyrosine kinases are involved. Treatment of C2C12 cells with H2O2 induces a dose-dependent increase in c-jun/c-fos heterodimer binding, specifically reverted by the cysteine derivative and glutathione precursor N-acetyl-L-cysteine (NAC). The observation that the induction by angiotensin II of both the AP1 DNA binding activity and DNA synthesis in quiescent C2C12 myoblasts is abolished by NAC strongly suggests a role for reactive oxygen intermediates (ROIs) in the intracellular transduction of angiotensin II signals for immediate early gene induction and for cell proliferation.
...
PMID:Reactive oxygen intermediates (ROIs) are involved in the intracellular transduction of angiotensin II signal in C2C12 cells. 775 83
Mitogen-activated protein (MAP) kinases are a multigene family activated by many extracellular stimuli. There are three groups of MAP kinases based on their dual phosphorylation motifs, TEY, TPY, and TGY, which are termed extracellular signal-regulated protein kinases (ERK1/2),
c-Jun
N-terminal kinases, and p38, respectively. A new MAP kinase family member termed Big MAP kinase 1 (BMK1) or ERK5 was recently cloned. BMK1 has a TEY sequence similar to ERK1/2 but has unique COOH-terminal and loop-12 domains. To define BMK1 regulation, its activation in cultured rat vascular smooth muscle cells was characterized.
Angiotensin II
, phorbol ester, platelet-derived growth factor, and tumor necrosis factor-alpha were the strongest stimuli for ERK1/2 but were weak activators of BMK1. In contrast, H2O2 caused concentration-dependent activation of BMK1 but not ERK1/2. Sorbitol activated both BMK1 and ERK1/2. BMK1 activation by H2O2 was calcium-dependent and appeared ubiquitous as shown by stimulation in human skin fibroblasts, human vascular smooth muscle cells, and human umbilical vein endothelial cells. These findings demonstrate that activation of BMK1 is different from ERK1/2 and suggest an important role for BMK1 as a redox-sensitive kinase.
...
PMID:Big mitogen-activated protein kinase 1 (BMK1) is a redox-sensitive kinase. 866 94
Angiotensin II
(
AII
) binds to specific G protein-coupled receptors and is mitogenic in adrenal, liver epithelial, and vascular smooth muscle cells. Since the cyclin D1 gene encodes the regulatory subunit of the cyclin D1-dependent kinase (CD1K) required for phosphorylation of the retinoblastoma protein (pRB), an essential and rate-limiting step in G1 phase progression of the cell cycle, we examined the effect of
AII
on cyclin D1 expression and CD1K activity in the human adrenal cell line H295R.
AII
(10(-6) M) stimulated G1 phase progression within 12 h, with a maximal effect after 72 h. This action was antedated by the induction of cyclin D1 mRNA (3-fold), cyclin D1 nuclear protein abundance (4-fold), and CD1K activity (4-fold).
AII
induced cyclin D1 promoter activity 4-fold, via the AT1 receptor through an enhancer sequence at -954 base pairs. c-Fos and
c-Jun
bound the cyclin D1 -954 enhancer sequence, and the abundance of c-Fos within this complex was increased by
AII
treatment.
AII
induced extracellular signal-regulated kinase (ERK) activity 7-fold, and dominant-negative mutants of either p21(ras) or ERK reduced
AII
-stimulated cyclin D1 promoter activity. These findings suggest that
AII
may stimulate mitogenesis by increasing CD1K activity through a p21(ras)/ERK/activator protein 1 pathway.
...
PMID:Angiotensin II activation of cyclin D1-dependent kinase activity. 879 25
The effects of intracerebroventricular (i.c.v.) injections of angiotensin II (
Ang II
) on the expression of inducible transcription factors (ITF) (c-Fos, FosB,
c-Jun
, JunB, JunD, Krox-20 and Krox-24) in the brain of conscious rats were assessed immunohistochemically using polyclonal antisera.
Ang II
(1, 10, 100 ng) induced after 90 min a dose-dependent expression of c-Fos, FosB,
c-Jun
, JunB and Krox-24, which was confined to four specific brain areas, namely the subfornical organ (SFO), median preoptic area (MnPO), paraventricular nucleus (PVN) and supraoptic nucleus (SON). In the above-mentioned regions, JunD exhibited a high basal staining which was not visibly altered by
Ang II
. Krox 20 was not induced by AnG II. FosB was only induced 4 h after i.c.v. injection of 100 ng
Ang II
in the MnPO and PVN. The
Ang II
-AT1 receptor antagonist, losartan, applied i.c.v. 5 min prior to
Ang II
(100 ng, i.c.v.) prevented the
Ang II
-induced ITF expression. In spontaneously hypertensive rats (SHR) but not in Wistar rats with nephrogenic hypertension due to aortic banding (WIab), the
Ang II
-induced expression of c-Fos, and
c-Jun
was enhanced in all four areas when compared to normotensive Wistar Kyoto (WKY)- and Wistar (WI) rats. The
Ang II
-induced expression of Krox-24 in the SFO, MnPO and PVN in SHR was also significantly increased when compared to WKY, WI and WIab rats. Our data demonstrate that a stimulation of periventricular
Ang II
-AT1 receptors induces a temporally and spatially highly differentiated expression pattern of ITFs restricted to four distinct regions of the forebrain involved in blood pressure regulation and body fluid homeostasis. The points to a strictly regulated expression of target genes in the respective regions. The enhanced
Ang II
-induced expression of ITFs in SHR compared to normotensive controls is not due to elevated blood pressure itself, since it was not observed in secondary hypertensive rats WIab. Thus, the increased sensitivity to
Ang II
in SHR appears to be genetically determined. The target genes regulated by
Ang II
-induced ITFs will have to be identified.
...
PMID:Complex activation of inducible transcription factors in the brain of normotensive and spontaneously hypertensive rats following central angiotensin II administration. 889 87
Many lines of evidence have suggested that angiotensin II (
Ang II
)plays an important role in cardiac hypertrophy.
Ang II
not only increases protein synthesis but also induces the reprogramming of gene expression in cultured cardiac myocytes. In the present study, to elucidate the mechanism by which
Ang II
regulates gene expression in cardiac myocytes, we examined whether
Ang II
activates
c-Jun
NH2-terminal kinase (JNK), which is a member of the mitogen-activated protein kinase family and activates the transcription factor, activator protein-1 (AP-1). The activity of JNK increased 5 minutes after the addition of
Ang II
, peaked at 20 minutes, and gradually decreased thereafter. Examination of the
Ang II
dose-response relation revealed detectable JNK activation at 10(-9) mol/L and maximal activation at 10(-6) mol/L.
Ang II
activated JNK through the AT1 receptor, and the activation was attenuated by the downregulation of protein kinase C or the chelation of intracellular Ca2+. Although the addition of either Ca2+ ionophore or phorbol ester resulted in little or no activation of JNK, simultaneous addition of both Ca2+ ionophore and phorbol ester markedly activated JNK. Slight expressions of the c-jun gene were observed in unstimulated cardiac myocytes, and
Ang II
increased expressions of the c-jun gene as well as the c-fos gene.
Ang II
increased transcription of the endothelin-1 gene through the AP-1 binding site. In conclusion,
Ang II
may activate JNK in cultured cardiac myocytes through an increase in intracellular Ca2+ and activation of protein kinase C, and the activated JNK may regulate gene expression by activating AP-1 during
Ang II
-induced cardiac hypertrophy.
...
PMID:Angiotensin II stimulates c-Jun NH2-terminal kinase in cultured cardiac myocytes of neonatal rats. 897 32
In rat liver epithelial cells (GN4), angiotensin II (
Ang II
) and thapsigargin stimulate a novel calcium-dependent tyrosine kinase (CADTK) also known as PYK2, CAKbeta, or RAFTK. Activation of CADTK by a thapsigargin-dependent increase in intracellular calcium failed to stimulate the extracellular signal-regulated protein kinase pathway but was well correlated with a 30-50-fold activation of c-Jun N-terminal kinase (JNK). In contrast,
Ang II
, which increased both protein kinase C (PKC) activity and intracellular calcium, stimulated extracellular signal-regulated protein kinase but produced a smaller, less sustained, JNK activation than thapsigargin. 12-O-Tetradecanoylphorbol 13-acetate (TPA), which slowly activated CADTK, did not stimulate JNK. These findings suggest either that CADTK is not involved in JNK activation or PKC activation inhibits the CADTK to JNK pathway. A 1-min TPA pretreatment of GN4 cells inhibited thapsigargin-dependent JNK activation by 80-90%. In contrast, TPA did not inhibit the >50-fold JNK activation effected by anisomycin or UV. The consequence of PKC-dependent JNK inhibition was reflected in
c-Jun
and c-Fos mRNA induction following treatment with thapsigargin and
Ang II
. Thapsigargin, which only minimally induced c-Fos, produced a much greater and more prolonged
c-Jun
response than
Ang II
. Elevation of another intracellular second messenger, cAMP, for 5-15 min also inhibited calcium-dependent JNK activation by approximately 80-90% but likewise had no effect on the stress-dependent JNK pathway. In summary, two pathways stimulate JNK in cells expressing CADTK, a calcium-dependent pathway modifiable by PKC and cAMP-dependent protein kinase and a stress-activated pathway independent of CADTK, PKC, and cAMP-dependent protein kinase; the inhibition by PKC can ultimately alter gene expression initiated by a calcium signal.
...
PMID:Protein kinase C and protein kinase A inhibit calcium-dependent but not stress-dependent c-Jun N-terminal kinase activation in rat liver epithelial cells. 916 74
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