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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 regulation of the basic fibroblast growth factor (bFGF, or
FGF-2
) receptor on porcine granulosa cells was studied. Receptor levels before and after cell differentiation in vivo and in vitro did not show any significant changes. Dibutyryl cAMP and the
protein kinase A
(
PKA
) inhibitor H-8 had no effect on bFGF binding. These results suggest that
PKA
was not involved in the receptor expression. Treatment of the granulosa cells with phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, progressively decreased the number of bFGF receptors to about 20% of their initial levels after 8 h, and this effect occurred in a concentration- and time-dependent manner. Similarly, synthetic diacylglycerol also inhibited bFGF binding. The highly specific PKC inhibitor GF109203X completely prevented the reduction of bFGF binding by PMA and diacylglycerol. Kinetic analyses of the turnover of cell surface bFGF receptors in the presence of cycloheximide showed that PMA accelerated loss of receptors from the cell surface, suggesting the enhanced receptor internalization by PMA resulting in the receptor reduction. PMA did not influence steady-state FGF receptor messenger RNA levels. PMA induced an increased PKC activity in the membrane fraction, and among PMA sensitive PKC alpha, beta II, delta and epsilon, only PKC alpha was readily detected by immunoblotting and translocated to the membrane fraction. PMA-pretreated cells showed negligible effect on c-fos messenger RNA induction in response to bFGF stimulation, indicating a functional reduction of receptors. When cells were incubated with epidermal growth factor, receptor levels were reduced, but this effect was not observed in the presence of GF109203X. These results suggest that the bFGF receptor in porcine granulosa cells is regulated by the PKC, not
PKA
, pathway in an isoenzyme-specific fashion and that its possible mechanism may involve regulation of receptor internalization.
...
PMID:Protein kinase C-dependent down-regulation of basic fibroblast growth factor (FGF-2) receptor by phorbol ester and epidermal growth factor in porcine granulosa cells. 762 83
Fibroblast growth factor (FGF)-1 mitogenic signal transduction is mediated in part by gene products that are specifically expressed in response to cell surface receptor binding and activation. We have used a targeted differential display method to identify FGF-1-inducible genes in murine NIH 3T3 fibroblasts. Here we report that one of these genes is predicted to encode a novel serine/threonine-specific protein kinase. This putative kinase has been named Fnk, for FGF-inducible kinase. The deduced Fnk amino acid sequence has 49, 36, 33, 32, and 22% overall identity to mouse serum-inducible kinase (Snk), mouse polo-like kinase (Plk), Drosophila polo, Saccharomyces Cdc5, and mouse Snk/Plk-akin kinase (Sak), respectively. These proteins are all members of the polo subfamily of structurally related serine/threonine kinases. The Plk, polo, Cdc5, and Sak kinases are required for cell division. FGF-1 induction of Fnk mRNA expression is first detected at 30 min after mitogen addition, reflects transcriptional activation, and does not require de novo protein synthesis.
FGF-2
, platelet-derived growth factor-BB, calf serum, or phorbol myristate acetate treatment of quiescent cells also induces fnk gene expression. Fnk mRNA is expressed in vivo in a tissue-specific manner, with relatively high levels detected in newborn and adult mouse skin. These results indicate that Fnk may be a transiently expressed
protein kinase
involved in the early signaling events required for growth factor-stimulated cell cycle progression.
...
PMID:Identification by targeted differential display of an immediate early gene encoding a putative serine/threonine kinase. 773 Mar 42
FGF-2
(basic fibroblast growth factor) was recently detected in the nucleus of a variety of cell types. The large isoforms contain a functional nuclear localization signal that allows their nuclear accumulation in producing cells, while a small amount of
FGF-2
added exogenously to target cells is translocated to the nucleus in phase G1 of the cell cycle according to an unknown process. We report here using Chinese hamster ovary cell mutants bearing deficiency in heparan sulfate proteoglycans (HSPGs) synthesis that HSPGs are required for transport of exogenous
FGF-2
to the nucleus. Furthermore a co-transport was suggested since an active complex containing
FGF-2
and HSPGs was isolated from nuclei of treated cells. Several
FGF-2
nuclear targets were described. In vivo as in vitro, it activates rDNA transcription and it binds to a specific DNA sequence that is present in the non-transcribed spacer of ribosomal genes. In vitro,
FGF-2
has a strong affinity for histone H1 and it activates the
protein kinase
CKII
. In the nucleus
FGF-2
could regulate gene expression through modulation of chromatin structure.
...
PMID:Fibroblast growth factor-2 (FGF-2) in the nucleus: translocation process and targets. 831 35
The subcellular fractions containing protein kinases capable of phosphorylating basic fibroblast growth factor (
FGF-2
) are unknown, but having previously characterized one that is associated with the plasma membrane [1991, Mol. Endocrinol. 5, 1003-1012] we evaluated the catalytic properties of another in the nucleus. The reaction is time (linear up to 15 min), enzyme (2,000-25,000 nuclei/ml), and substrate (Km 0.18 microM) dependent, and the targets serine. DNase pretreatment of nuclei decreases the incorporation of phosphate into
FGF-2
by 50% and the reaction. It is also inhibited by heparin (EC50 1 microgram/ml) and spermidine (EC50 3 microM). Calcium and cAMP have no effect. We conclude that the kinase is distinct from
PKA
, and PKC, and suggest that changes in glycosaminoglycan and polyamine concentrations during the cell cycle may modulate
FGF-2
phosphorylation in the nucleus, or as it is translocated to the nucleus.
...
PMID:Phosphorylation of basic fibroblast growth factor (FGF-2) in the nuclei of SK-Hep-1 cells. 839 11
Fibroblast growth factors (FGFs) play a role in biological processes such as cell growth and development, angiogenesis, and wound healing. Several genes have been shown to be induced by FGFs, but the underlying mechanisms have not been elucidated. We investigated the effect of
FGF-2
(basic FGF) on the urokinase-type plasminogen activator (uPA) gene in NIH 3T3 fibroblasts. We found that the uPA gene is transcriptionally induced by
FGF-2
as well as by 12-O-tetradecanoylphorbol-13 -acetate involving a PEA3/AP1 element located 2.4 kb upstream of the transcription initiation site; neither induction requires ongoing protein synthesis. Unlike 12-O-tetradecanoylphorbol-13-acetate induction,
FGF-2
induction was not impaired by protein kinase C down-regulation. Analyses of various signaling molecules by Western blotting, extracellular signal-regulated kinase (ERK) activity assays, and transient transfection assays (cotransfection of a uPA-reporter gene construct with expression vectors for wild-type or dominant negative type of these molecules or for ERK-specific protein phosphatase MKP-1) showed that a Ras/
Raf-1
/MEK/ERK-2/JunD pathway is induced by
FGF-2
and 12-O-tetradecanoylphorbol-13-acetate, leading to the activation of the uPA gene.
...
PMID:Elucidation of a signaling pathway induced by FGF-2 leading to uPA gene expression in NIH 3T3 fibroblasts. 854 15
U46619, a thromboxane A2 analogue, and basic fibroblast growth factor (
FGF-2
) both induced the expression of the inducible cyclo-oxygenase (Cox)-2 in porcine aortic smooth-muscle cells. This induction was dose-dependent (submaximal at 300 nM for U46619 and 1 ng/ml for
FGF-2
) and time-dependent, with similar intensity and maximal expression at 2 h. Under these conditions, both inducers stimulated rapid activation of extracellular signal-regulated kinase (ERK2) at 5-10 min, a transient and lower intensity being induced by U46619 whereas that induced by
FGF-2
was sustained (>1 h). PD98059, an inhibitor of the ERK pathway, inhibited the expression of Cox-2. In contrast, activation of Jun-N-terminal kinase (JNK1) was sustained with U46619 but poorly induced by
FGF-2
. Cox-2 expression induced by U46619 or
FGF-2
was similarly reduced by prostaglandin (PGE2), forskolin or dibutyryl-cAMP, suggesting a regulatory effect of adenylate cyclase on Cox-2 expression. However, activation of ERK2 by
FGF-2
was not affected by PGE2 whereas that of JNK1 by U46619 was inhibited, suggesting that inhibition of COX-2 expression by cAMP may be downstream of ERK2. The effects of PGE2 and forskolin on Cox-2 and phosphorylation of JNK1 were reversed with the
protein kinase A
inhibitor H89. In addition, endogenous PGE2 down-regulated the expression of Cox-2 by the two inducers, as stimulation of the cells in the presence of different Cox inhibitors increased the expression of the protein. Overall, these results suggest that exogenous and endogenous PGE2 exert negative inhibitory effects on Cox-2 expression mediated by stimulation of
protein kinase A
.
...
PMID:Regulatory role of prostaglandin E2 in induction of cyclo-oxygenase-2 by a thromboxane A2 analogue (U46619) and basic fibroblast growth factor in porcine aortic smooth-muscle cells. 929 Nov 37
The mRNA expressions of various growth regulatory molecules in single human anagen hair follicles were analysed by reverse transcription and polymerase chain reaction. Approximately 370 hair follicles were isolated from 20 normal individuals, and 0.90 +/- 0.34 microgram (mean +/- SD) total RNA was extracted per whole hair follicle. The mRNAs of fibroblast growth factor (FGF)-1,
FGF-2
, FGF-5, FGF-7, transforming growth factor (TGF)-alpha, TGF-beta 1, hepatocyte growth factor, insulin-like growth factor (IGF)-I, tumour suppressor gene p53 and high sulphur protein were detected in most or all of the examined hair follicles per target gene. In contrast, none of the mRNAs of FGF-3, FGF-4, FGF-6, FGF-9 and IGF-II was detected, and those of TGF-beta 2 and TGF-beta 3 were detected in only a limited number of the examined hair follicles. Among
cyclin-dependent kinase
inhibitors, the mRNAs of p21waf1/cip1 and p27kip1 were expressed in almost all the hair follicles, while those of p15INK4B and p16INK4A were not detected. These results suggest that both positive and negative factors for the proliferation and differentiation of follicular epithelial cells coexist in a human anagen hair follicle.
...
PMID:Genes for a range of growth factors and cyclin-dependent kinase inhibitors are expressed by isolated human hair follicles. 941 26
We recently demonstrated the activation of extracellular signal- regulated
protein kinase
1 and 2 (ERK1 and ERK2) by IGF-1,
FGF-2
, and PDGF-BB in normal human osteoblastic (HOB) cells as well as in rat and mouse osteoblastic cells. In this report, we have examined whether c-Jun NH2-Terminal Kinase (JNK) pathway is activated by growth factors and interleukin-1 beta (IL-1 beta) in normal HOB and rat UMR-106 cells using immune-complex kinase assay and anti-active JNK antibody, which recognizes activated forms of both JNK1 and JNK2. Results have demonstrated the presence of JNK1 and JNK2 proteins in normal HOB and UMR-106 cells. Both JNK1 and JNK2 were activated by IL-1 beta. IL-1 beta preferentially activated JNK pathway in a dose- and time-dependent manner and had little effect on ERK pathway. On the other hand,
FGF-2
did not activate JNK but most strongly activated ERK pathway. The activation of JNK was maximal at 20 min whereas maximal activation of ERK1 and ERK2 was observed within 10 min. Results have clearly demonstrated that IL-1 beta preferentially activates JNK pathway whereas
FGF-2
activates ERK pathway in normal human and rat UMR-106 osteoblastic cells.
...
PMID:Activation of c-Jun NH2-terminal kinases by interleukin-1 beta in normal human osteoblastic and rat UMR-106 cells. 951 50
Polypeptide growth factors activate common signal transduction pathways, yet they can induce transcription of different target genes. The mechanisms that control this specificity are not completely understood. Recently, we have described a fibroblast growth factor (FGF)-inducible response element, FiRE, on the syndecan-1 gene. In NIH 3T3 cells, the FiRE is activated by
FGF-2
but not by several other growth factors, such as platelet-derived growth factor or epidermal growth factor, suggesting that
FGF-2
activates signaling pathways that diverge from pathways activated by other growth factors. In this paper, we report that the activation of FiRE by
FGF-2
requires
protein kinase A
(
PKA
) in NIH 3T3 cells. The
PKA
-specific inhibitor H-89 (N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide) blocked the
FGF-2
-induced activation of FiRE, the transcription of the syndecan-1 gene, and cell proliferation. Also, expression of a dominant-negative form of
PKA
inhibited the
FGF-2
-induced FiRE activation and the transcription of the syndecan-1 gene. The binding of activator protein-1 transcription-factor complexes, required for the activation of FiRE, was blocked by inhibition of
PKA
activity before
FGF-2
treatment. In accordance with the growth factor specificity of FiRE, the activity of
PKA
was stimulated by
FGF-2
but not by platelet-derived growth factor or epidermal growth factor. Furthermore, a portion of the
PKA
catalytic subunit pool was translocated to the nucleus by
FGF-2
. Noticeably, the total cellular cAMP concentration was not affected by
FGF-2
stimulus. We propose that the
FGF-2
-selective transcriptional activation through FiRE is caused by the ability of
FGF-2
to control
PKA
activity.
...
PMID:Involvement of protein kinase A in fibroblast growth factor-2-activated transcription. 1061 89
Developing cardiac myocytes divide a limited number of times before they stop and terminally differentiate, but the mechanism that stops their division is unknown. To help study the stopping mechanism, we defined conditions under which embryonic rat cardiac myocytes cultured in serum-free medium proliferate and exit the cell cycle on a schedule that closely resembles that seen in vivo. The culture medium contains FGF-1 and
FGF-2
, which stimulate cell proliferation, and thyroid hormone, which seems to be necessary for stable cell-cycle exit. Time-lapse video recording shows that the cells within a clone tend to divide a similar number of times before they stop, whereas cells in different clones divide a variable number of times before they stop. Cells cultured at 33 degrees C divide more slowly but stop dividing at around the same time as cells cultured at 37 degrees C, having undergone fewer divisions. Together, these findings suggest that an intrinsic timer helps control when cardiac myocytes withdraw from the cell cycle and that the timer does not operate by simply counting cell divisions. We provide evidence that the
cyclin-dependent kinase
inhibitors p18 and p27 may be part of the timer and that thyroid hormone may help developing cardiac myocytes stably withdraw from the cell cycle.
...
PMID:An intrinsic timer that controls cell-cycle withdrawal in cultured cardiac myocytes. 1064
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