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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Physiological mechanical loading is crucial for maintenance of bone integrity and architecture. We have calculated the strain caused by gravity stress on osteoblasts and found that 4-30g corresponds to physiological levels of 40-300 microstrain. Short-term gravity loading (15 minutes) induced a 15-fold increase in expression of growth-related immediate early gene
c-fos
, a 5-fold increase in egr-1, and a 3-fold increase in autocrine bFGF. The non-growth-related genes EP-1, TGF-beta, and 18s were unaffected by gravity loading. Short-term physiological loading induced extracellular signal-regulated kinase (ERK 1/2) phosphorylation in a dose-dependent manner with maximum phosphorylation saturating at mechanical loading levels of 12g (p < 0.001) with no effect on total ERK. The phosphorylation of
focal adhesion kinase
(
FAK
) was unaffected by mechanical force. g-Loading did not activate P38 MAPK or c-jun N-terminal kinase (JNK). Additionally, a gravity pulse resulted in the localization of phosphorylated ERK 1/2 to the nucleus; this did not occur in unloaded cells. The induction of
c-fos
was inhibited 74% by the MEK1/2 inhibitor U0126 (p < 0.001) but was not affected by MEK1 or p38 MAPK-specific inhibitors. The long-term consequence of a single 15-minute gravity pulse was a 64% increase in cell growth (p < 0.001). U0126 significantly inhibited gravity-induced growth by 50% (p < 0.001). These studies suggest that short periods of physiological mechanical stress induce immediate early gene expression and growth in MC3T3-E1 osteoblasts primarily through an ERK 1/2-mediated pathway.
...
PMID:A short pulse of mechanical force induces gene expression and growth in MC3T3-E1 osteoblasts via an ERK 1/2 pathway. 1251 Aug 6
We have characterized the transduction pathways induced by leptin in the placenta, using human BeWo cells that express endogenous leptin receptors and synthesize leptin in a regulated manner. We first examined if the JAK-STAT phosphorylation cascade was functional in these cells. Phosphorylated
JAK2
was primarily bound to a short 106kDa leptin receptor isoform and to a lesser extent to a 210kDa molecule. Leptin neither enhanced
JAK2
phosphorylation nor activated STAT3 and STAT1 proteins indicating that
JAK2
is constitutively activated and that the JAK-STAT transduction pathway is not recruited by leptin in BeWo cells. By contrast, leptin stimulated the transcription of the
c-fos
gene (3-fold) and cell proliferation (2-fold) as measured by DNA synthesis. Both effects were dependent on the rapid phosphorylation of p42-44 MAPK but not p38 MAPK. We conclude that a functional JAK-STAT pathway is not required for leptin to transduce proliferative signals in human placental cells. These findings extend the physiological action of leptin beyond its central effects, to the control of placental gene transcription and cell proliferation.
...
PMID:Transduction of leptin growth signals in placental cells is independent of JAK-STAT activation. 1265 12
The ability of nonpeptide antagonists to interact with gastrin releasing peptide receptors on lung cancer cells was investigated. PD176252 (3-(1H-Indol-3-yl)-N-[1-(5-methoxy-pyridin-2-yl)-cyclohexylmethyl]-2-methyl-2-[3-(4-nitro-phenyl)-ureido]-propionamide) and PD168368 (3-(1H-Indol-3-yl)-2-methyl-2-[3(4-nitro-phenyl)-ureido]-N-(1-pyridin-2-yl-cyclohexylmethyl)-propionamide) inhibited specific 125I-gastrin releasing peptide binding to NCI-H1299 cells with IC50 values of 20 and 1500 nM, respectively. Similar binding results were obtained using NCI-H157, H345 and N592 human lung cancer cells. PD176252 inhibited the ability of 1 nM bombesin to cause elevation of cytosolic calcium in Fura-2 loaded NCI-H345 or H1299 cells, whereas it had no effect on basal cytosolic calcium. PD176252 antagonized the ability of 10 nM bombesin to cause elevation of
c-fos
mRNA in NCI-H1299 cells. Also, PD176252 inhibited the ability of 100 nM bombesin to cause tyrosine phosphorylation of
focal adhesion kinase
in NCI-H1299 cells. Using a [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay, PD176252 was more potent than PD168368 at inhibiting NCI-H1299 proliferation. Also, 1 microM PD176252 significantly inhibited lung cancer colony number in vitro. PD176252 in a dose-dependent manner inhibited NCI-H1299 xenograft growth in nude mice in vivo. These results indicate that PD176252 is a gastrin releasing peptide receptor antagonist, which inhibits the proliferation of lung cancer cells.
...
PMID:Nonpeptide gastrin releasing peptide receptor antagonists inhibit the proliferation of lung cancer cells. 1290 92
Neuroendocrine (NE) cells are found in prostate tumors, and their incidence is considered a promising prognostic indicator for the development of androgen-independent disease. NE cells are derived from non-NE prostate cancer cells and secrete factors that can act in a paracrine manner to stimulate the survival, growth, motility, and metastatic potential of prostatic carcinoma cells. Factors such as IL-6, epinephrine, and forskolin induce NE differentiation in prostate cancer cells; the mechanisms involve increases in intracellular cAMP, protein kinase A (PKA) activation and reduced intracellular calcium levels. Transcription factors implicated in the acquisition of NE characteristics by prostate cancer cells include STAT3, CREB, EGR1,
c-fos
, and NF-kappaB. Expression of Chromogranin A, neuron-specific enolase, bcl-2, and the androgen receptor are modulated during NE differentiation and serve as molecular markers for NE cells. Most importantly, NE cells secrete neuropeptides, such as bombesin, neurotensin, PTHrP, serotonin, and calcitonin, which trigger growth and survival responses in androgen-independent prostate cancer cells. Prostate cancer cell receptors that play a role in these processes include the gastrin-releasing peptide (GRP) receptor, neurotensin receptors, and the epidermal growth-factor receptor (EGFR). Signal-transduction molecules activated by these neuropeptides include Src,
focal adhesion kinase
(
FAK
), ERK, and PI3K/Akt, with subsequent activation of Elk-1, NF-kappaB, and c-myc transcription factors. A multitude of genes are then expressed by prostate cancer cells, which are involved in proliferation, anti-apoptosis, migration, metastasis, and angiogenesis. Targeting of these pathways at multiple levels can be exploited to inhibit the process by which NE cells contribute to the progression of androgen-independent, treatment-refractory prostate cancer.
...
PMID:Neuroendocrine cells in prostate cancer. 1566 58
The LIM protein Hic-5 is a focal adhesion protein shuttling in and out of the nucleus through the redox-sensitive nuclear export signal, and unlike other focal adhesion proteins including paxillin, the protein most homologous to Hic-5, it accumulates in the nucleus under oxidative conditions and participates in the transcription of
c-fos
and p21(Cip1) genes. Here, we examined the roles of the interacting partners of Hic-5,
focal adhesion kinase
(
FAK
) and protein tyrosine phosphatase PEST (PTP-PEST), in the nuclear translocation of Hic-5 and found that they were inhibitory. Interestingly, the interaction of Hic-5 with
FAK
was regulated by specific cysteines near the binding site and decreased in cells under oxidative conditions. Its interaction with PTP-PEST was also sensitive to the oxidant. These results suggest that the nuclear-cytoplasmic shuttling of Hic-5 is regulated by its interacting partners at focal adhesions or in the cytoplasm in a redox-sensitive manner, coordinating its role at focal adhesions with that in the nucleus, depending on the redox state of cells. Cytochalasin D or a phorbol ester also induced nuclear accumulation of Hic-5, which was inhibited by scavengers of reactive oxygen species (ROS), suggesting that besides oxidants, endogenously produced ROS induced the nuclear accumulation of Hic-5.
...
PMID:Involvement of FAK and PTP-PEST in the regulation of redox-sensitive nuclear-cytoplasmic shuttling of a LIM protein, Hic-5. 1570 82
Signal transducer and activator of transcription 3 (STAT3) has been indirectly implicated in numerous fundamental cellular processes, including proliferation, survival, and differentiation. We provide genetic evidence from studies of STAT3-null cells that STAT3 is dispensable for normal growth of mouse fibroblasts in culture. STAT3 contributed to the full induction of some (typified by
c-fos
) but not all (typified by c-myc) immediate early gene expression, but STAT3-independent processes were sufficient to support full cell growth and survival. However, STAT3 was required to manifest a transformed state following expression of v-src, and STAT3-null cells were impaired for anchorage-independent growth as colonies in soft agar and as tumors in mice. The data suggest that STAT3 mediates the maintenance of
focal adhesion kinase
activity in the absence of cell adhesion by suppressing the action of an inhibitory phosphatase.
...
PMID:Malignant transformation but not normal cell growth depends on signal transducer and activator of transcription 3. 1599 59
RANKL plays a pivotal role in the differentiation, function and survival of osteoclasts, the principal bone-resorbing cells. RANKL exerts the effects by binding RANK, the receptor activator of NF-kappaB, in osteoclasts and its precursors. Upon binding RANKL, RANK activates six major signaling pathways: NFATc1, NF-kappaB, Akt/
PKB
, JNK, ERK and p38, which play distinct roles in osteoclast differentiation, function and survival. Recent studies have not only provided more insights into RANK signaling but have also revealed that several factors, including INF-gamma, IFN-beta, and ITAM-activated costimulatory signals, regulate osteoclastogenesis via direct crosstalk with RANK signaling. It was recently shown that RANK contains three functional motifs capable of mediating osteoclastogenesis. Moreover, although both IFN-gamma and IFN-beta inhibit osteoclastogenesis, they exert the inhibitory effects by distinct mechanisms. Whereas IFN-gamma has been shown to block osteoclastogenesis by promoting degradation of TRAF6, IFN-beta inhibits osteoclastogenesis by down-regulating
c-fos
expression. In contrast, the ITAM-activated costimulatory signals positively regulate osteoclastogenesis by mediating the activation of NFATc1 through two ITAM-harboring adaptors: FcRgamma and DAP12. This review is focused on discussing the current understanding of RANK signaling and signaling crosstalk between RANK and the various factors in osteoclasts.
...
PMID:RANKing intracellular signaling in osteoclasts. 1601 47
Little information was found in the literature about the expression on hydroxyapatite (HA) materials of genes specific of cellular adhesion molecules although more were found on titanium-based substrates. Hence, the goal of this work was to study by a kinetic approach from 30 min to 4 days the adhesion of Saos-2 cells on microporous (mHA) and non-microporous hydroxyapatite (pHA) in comparison to polished titanium. Our strategy associated the visualization of adhesion proteins inside the cells by immunohistochemistry and the quantitative expression of genes at mRNA level by real-time PCR. The cell morphology was assessed using scanning electron microscopy and the number of cells thanks to biochemical techniques. The cellular attachment was the highest on mHA from 30 min to 24 h although the cell growth on mHA was the lowest after 4 days. Generally, the Saos-2 osteoblastic cells morphology on mHA was radically different than on other surfaces with the particularity of the cytoplasmic edge, which appeared un-distinguishable from the surface. The revelation by specific antibodies of proteins of the cytoskeleton (actin) and the focal adhesions (
FAK
, phosphotyrosine) confirmed that adhesion and spreading were different on the 3 materials. The actin stress fibres were less numerous and shorter on mHA ceramics. Cells had more focal contacts after 4 h on mHA compared to other substrates but less after 24 h. The highest values of total proteins were extracted from mHA at 0.5 and 24 h and from pHA at 1, 4, and 96 h. The alphav and beta1 integrin, actin,
FAK
, and ERK gene expression were found to be different with adhesion time and with materials. C-jun expression was comparable on mHA, titanium and plastic but was largely higher than on pHA at 0.5 and 1 h. On the contrary,
c-fos
expression was the highest on pHA after 0.5 h and the lowest after 1h. This difference between
c-fos
and c-jun expression on pHA after 0.5 h could be related to the fact that these two genes may differ in their signalling pathways. The expression of the alkaline phosphatase gene after 4 days was lower on mHA compared to other materials demonstrating that the microstructure of the mHA ceramic was not favourable to Saos-2 cells differentiation. Finally, it was demonstrated in this study that HA and titanium surfaces influence as well gene expression at early times of adhesion as the synthesis of adhesion proteins but also proliferation and differentiation phases. Indeed, the signal transduction pathways involved in adhesion of Saos-2 cells on HA and titanium were confirmed by the sequential expression of alphav and beta1 integrins,
FAK
, and ERK genes followed by the expression of c-jun and
c-fos
genes for proliferation and alkaline phosphatase gene for differentiation.
...
PMID:Quantitative kinetic analysis of gene expression during human osteoblastic adhesion on orthopaedic materials. 1642 24
Prolactin (PRL) is a polypeptide hormone produced by the anterior pituitary gland and other sites that acts both systemically and locally to cause lactation and other biological effects by interacting with the PRL receptor, a Janus kinase (JAK)2-coupled cytokine receptor family member, and activating downstream signal pathways. Recent evidence suggests PRL is a player in the pathogenesis and progression of breast cancer. Epidermal growth factor (EGF) also has effects on breast tissue, working through its receptors, epidermal growth factor receptor (EGFR) and ErbB-2 (c-neu, HER2), both intrinsic tyrosine kinase growth factor receptors. EGFR promotes pubertal breast ductal morphogenesis in mice, and both EGFR and ErbB-2 are relevant in pathogenesis and behavior of breast and other human cancers. Previous studies showed that PRL and EGF synergize to enhance motility in the human breast cancer cell line, T47D. In this study, we explored crosstalk between the PRL and EGF signaling pathways in T47D cells, with an ultimate aim of understanding how these two important factors might work together in vivo to affect breast cancer behavior. Both PRL and EGF caused robust signaling in T47D cells; PRL acutely activated
JAK2
, signal transducer and activator of transcription-5 (STAT5), and extracellular signal-regulated kinase-1 and -2 (ERK1 and ERK2), whereas EGF caused EGFR activation and consequent src homology collagen (SHC) activation and ERK activation. Notably, PRL also caused phosphorylation of the EGFR and ErbB-2 at sites detected by PTP101, an antibody that recognizes threonine phosphorylation at consensus motifs for ERK-induced phosphorylation. PRL-induced PTP101-reactive phosphorylation was prevented by pretreatment with PD98059, an ERK pathway inhibitor. Furthermore, PRL synergized with EGF in activating SHC and ERK and transactivating a luciferase reporter driven by
c-fos
gene enhancer elements, suggesting that PRL allowed markedly enhanced EGF signaling. This was accompanied by substantial inhibition of EGF-induced EGFR downregulation when PRL and EGF cotreatment was compared to EGF treatment alone. This effect of PRL was abrogated by ERK pathway inhibitor pretreatment. Our data suggest that PRL synergistically augments EGF signaling in T47D breast cancer cells at least in part by lessening EGF-induced EGFR downregulation and that this effect requires PRL-induced ERK activity and threonine phosphorylation of EGFR.
...
PMID:Prolactin modulates phosphorylation, signaling and trafficking of epidermal growth factor receptor in human T47D breast cancer cells. 1678 91
Insulin exerts pleiotropic effects at the cellular level. Signaling via the two isoforms of the insulin receptor (IR) may explain the activation of different signaling cascades, while it remains to be explored how selectivity is achieved when utilizing the same IR isoform. We now demonstrate that insulin-stimulated transcription of
c-fos
and glucokinase genes is activated simultaneously in the insulin-producing beta-cell via IR-B localized in different cellular compartments. Insulin activates the glucokinase gene from plasma membrane-standing IR-B, while
c-fos
gene activation is dependent on clathrin-mediated IR-B-endocytosis and signaling from early endosomes. Moreover, glucokinase gene up-regulation requires the integrity of the juxtamembrane IR-B NPEY-motif and signaling via PI3K-C2alpha-like/PDK1/
PKB
, while
c-fos
gene activation requires the intact C-terminal YTHM-motif and signaling via PI3K Ia/Shc/MEK1/ERK. By using IR-B as an example it is thus possible to demonstrate how spatial segregation allows simultaneous and selective signaling via the same receptor isoform in the same cell.
...
PMID:Selective gene activation by spatial segregation of insulin receptor B signaling. 1726 62
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