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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)
Monocyte influx and activation in synovial joints are important in the pathogenesis of both degenerative and inflammatory arthropathies. In this study, we demonstrate the potential of articular cartilage to directly modulate these events. IL-1-stimulated human articular chondrocytes transcribed 0.7-kb monocyte chemoattractant protein-1 (MCP-1) mRNA. In situ hybridization of cartilage organ cultures revealed MCP-1 transcripts in chondrocytes in the superficial tangential zone within 2 h of stimulation with IL-1. Chondrocytes in deeper layers responded by 4 h and reached maximum MCP-1 mRNA levels by 8-12 h. IL-1-stimulated cartilage organ and chondrocyte monolayer cultures released functional monocyte chemotactic activity. This was neutralized by a monoclonal antibody specific for MCP-1, and was associated with the synthesis and secretion of immunoreactive 13-kD and 15-kD isoforms of MCP-1. Regulators and signal transduction pathways involved with the expression of the MCP-1 gene in chondrocytes were analyzed. Steady-state mRNA levels were increased by the known chondrocyte activators IL-1, tumor necrosis factor alpha, LPS, platelet-derived growth factor, and transforming growth factor beta. In addition,
leukemia inhibitory factor
induced MCP-1 gene expression and protein synthesis, identifying this cytokine as a new regulator of chondrocyte function. Dexamethasone blunted the induction of MCP-1 gene expression by IL-1 and by activators of
protein kinase A
as well as protein kinase C signal transduction pathways. In contrast, retinoic acid strongly increased phorbol myristate acetate-induced MCP-1 expression and potentiated the effects of IL-1 and LPS. In conclusion, chondrocytes express MCP-1 in response to factors that are present in cartilage or synovium. This provides a mechanism by which cartilage can play an active role in the initiation and progression of arthritis.
...
PMID:Monocyte chemoattractant protein-1 (MCP-1) expression in human articular cartilage. Induction by peptide regulatory factors and differential effects of dexamethasone and retinoic acid. 136 41
Bafilomycin A1, a selective inhibitor of vacuolar H+-ATPase, time- and dose-dependently induced the differentiation of M1 cells, a murine myeloid leukemic cell line, into macrophage-like cells as revealed by the phagocytosis of polystyrene latex particles. This differentiation was inhibited not only by actinomycin D and cycloheximide but also by ST-638 (an inhibitor of tyrosine kinase). However, it was affected neither by K-252a (an inhibitor of C-kinase) nor by H-89 (an inhibitor of
A-kinase
), in contrast to the M1 cell differentiation induced by leukemia inhibitory factor (LIF). Okadaic acid inhibited both the bafilomycin A1-induced and
LIF
-induced differentiation of M1 cells.
...
PMID:Induction of phagocytic activity of M1 cells by an inhibitor of vacuolar H+-ATPase, bafilomycin A1. 750 42
The mechanisms of signaling pathways shared by interleukin (IL)-11, IL-6, leukemia inhibitory factor (LIF), and oncostatin M (ONC) remain elusive. We report here that treatment of 3T3-L1 cells with IL-11, IL-6,
LIF
, and ONC induces overlapping but distinct patterns of tyrosine phosphorylation and activates indistinguishable primary response genes. We further demonstrate for the first time that IL-11, IL-6,
LIF
, and ONC can trigger the activation of mitogen-activated protein kinases and the 85-92-kDa
ribosomal S6 protein kinase
(pp90rsk). In addition, our data also show that preincubation of cells with a tyrosine kinase inhibitor herbimycin A, but not with a serine/threonine kinase inhibitor H7, blocks activation of mitogen-activated protein kinases and pp90rsk. Interestingly, H7, but not herbimycin A, inhibits pp90rsk activity in the in vitro kinase assays. These results suggest that pp90rsk is one of the potential candidates for the H7-sensitive
protein kinase
(s), which is critical for the activation of primary response genes by these cytokines.
...
PMID:Mitogen-activated protein kinases and ribosomal S6 protein kinases are involved in signaling pathways shared by interleukin-11, interleukin-6, leukemia inhibitory factor, and oncostatin M in mouse 3T3-L1 cells. 750 17
We show here that treatment of 3T3-L1 cells with leukemia inhibitory factor (LIF) stimulates the activation of mitogen-activated protein kinase kinase (MAPKK), mitogen-activated protein kinase (MAPK), and S6
protein kinase
(S6K) activities both in a time- and dose-dependent manner. A single peak of MAPKK activity, four peaks of activity against the S6 synthetic peptide, RRLSSLRA (S6 peptide), and three distinct peaks toward myelin basic protein (MBP) were observed after Mono-Q chromatography of
LIF
-stimulated cell extracts. Two of the MBP kinase activities correlated with the stimulation of extracellular signal-regulated kinases 1 and 2. Interestingly, down-regulation of protein kinase C (PKC) by chronic treatment of 3T3-L1 cells with phorbol ester was found to attenuate, but not block, the
LIF
-mediated stimulation of MAPKK, MAPK, and S6K activities in 3T3-L1 cells. Treatment of 3T3-L1 cells with epidermal growth factor increased MAPKK, MAPK, and S6K activities to a similar extent as
LIF
, but this activation was not attenuated by down-regulation of PKC. Our results suggest that the full activation of the MAPK cascade by
LIF
may require inputs from multiple signaling pathways, one of which is dependent upon the presence of functional PKC.
...
PMID:Involvement of protein kinase C during activation of the mitogen-activated protein kinase cascade by leukemia inhibitory factor. Evidence for participation of multiple signaling pathways. 750 1
Ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), oncostatin M (OSM), and interleukin-6 (IL6) compose a family of distantly related cytokines that initiate signaling by inducing either homodimerization of the "beta" signal transducing receptor component gp130 (in the case of IL6) or heterodimerization between gp130 and the gp130-related LIFR beta (in the case of CNTF,
LIF
, and OSM); dimerization of beta receptor components in turn activates members of the Jak/Tyk family of receptor-associated tyrosine kinases. Here we report that CNTF,
LIF
, OSM, and IL6 induce most of the same protein tyrosine phosphorylations, regardless of the cell type assayed or whether they initiate signaling by inducing homo- or heterodimerization of beta components. Although several of the protein tyrosine phosphorylations induced by the CNTF/
LIF
/OSM/IL6 family of factors may correspond to novel tyrosine kinase targets, we have been able to demonstrate the involvement of known signaling molecules, such as phospholipase C gamma, phosphoinositol 3-kinase, phosphotyrosine phosphatase (PTP1D), pp120, SHC, GRB2, STAT91,
Raf-1
, and the mitogen-activated protein kinases ERK1 and ERK2, revealing substantial convergence not only between the pathways activated by this cytokine family and other cytokines, but with pathways previously known to be activated only by factors that utilize receptor tyrosine kinases. Our data suggest the beta receptor components can form complexes with some of the signaling proteins identified and may play some role in their recruitment.
...
PMID:Ciliary neurotrophic factor/leukemia inhibitory factor/interleukin 6/oncostatin M family of cytokines induces tyrosine phosphorylation of a common set of proteins overlapping those induced by other cytokines and growth factors. 751 71
The cytokines leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF) have been implicated in determination of neuronal phenotype as well as promotion of neuronal survival. However, the intracellular mechanisms by which their signals are transduced remain poorly understood. We have previously studied the regulation of vasoactive intestinal polypeptide gene expression by
LIF
and CNTF in the NBFL neuroblastoma cell line. Because these cytokines induce tyrosine phosphorylation that may lead to Ras activation, we explored a possible role for Ras in
LIF
- and CNTF-induced signal transduction. In NBFL cells
LIF
increases activated Ras in a rapid, transient, and concentration-dependent manner. CNTF and a related cytokine, oncostatin M, produce similar increases. CNTF and
LIF
also increase activated Ras in neuron-enriched dissociated cultures of sympathetic ganglia. Moreover, these cytokines rapidly and transiently induce specific tyrosine-phosphorylated proteins, p165 and p195. The
protein kinase
inhibitors K252a and staurosporine block
LIF
-induced increases in tyrosine phosphorylation, activated Ras, and vasoactive intestinal polypeptide mRNA in NBFL cells. These data support a possible role for Ras in the cell differentiation effects of
LIF
and CNTF.
...
PMID:Leukemia inhibitory factor and ciliary neurotrophic factor increase activated Ras in a neuroblastoma cell line and in sympathetic neuron cultures. 752 87
Raf-1
is a 74-kD serine/threonine kinase located in the cell cytoplasm that is activated by phosphorylation in cells stimulated with a variety of mitogens and growth factors, including hematopoietic growth factors. Using c-raf antisense oligonucleotides to block
Raf-1
expression, we have established that
Raf-1
is required for hematopoietic growth factor-induced proliferation of murine cell lines stimulated by growth factors whose receptors are members of several different structural classes: (a) the hematopoietin receptor family, including interleukin (IL)-2, IL-3, IL-4, granulocyte colony-stimulating factor, granulocyte/macrophage colony-stimulating factor (GM-CSF), and erythropoietin; (b) the tyrosine kinase receptor class, including Steel factor and CSF-1; and (c) IL-6,
leukemia inhibitory factor
, and oncostatin M, whose receptors include the gp130 receptor subunit. Although results of previous experiments had suggested that IL-4 does not phosphorylate or activate the
Raf-1
kinase, c-raf antisense oligonucleotides inhibited IL-4-induced proliferation of both myeloid and T cell lines, and IL-4 activated
Raf-1
kinase activity in an IL-4-dependent myeloid cell line. In colony assays, c-raf antisense oligonucleotides completely inhibited colony formation of unseparated normal murine bone marrow cells stimulated with either IL-3 or CSF-1 and partially inhibited cells stimulated with GM-CSF. In addition, c-raf antisense oligonucleotides completely inhibited both IL-3- and GM-CSF-induced colony formation of CD34+ purified human progenitors stimulated with these same growth factors. Thus,
Raf-1
is required for growth factor-induced proliferation of leukemic murine progenitor cell lines and normal murine and human bone marrow-derived progenitor cells regardless of the growth factor used to stimulate cell growth.
...
PMID:Raf-1 protein is required for growth factor-induced proliferation of hematopoietic cells. 753 43
Bacterial LPS induce production of cytokines such as IL-1, IL-6, and TNF in mononuclear phagocytes, and this represents a central component in the pathogenesis of septic shock syndrome. However, the mechanisms by which LPS activates these cells to express cytokines are not completely characterized. The present study addressed the role of different protein kinases in the LPS induction of cytokines. It is shown that LPS induced a 12- to 16-fold increase in IL-1 beta, IL-6, and TNF-alpha mRNA levels, and this was completely or more than 80% blocked by the protein tyrosine kinase specific inhibitors herbimycin A and genistein at the concentrations of 1.7 and 37 microM, respectively. Protein kinase C inhibition by staurosporine reduced LPS induction of TNF-alpha, whereas it had no effects on IL-6 and IL-1 beta. Inhibition of
protein kinase A
by H89 reduced IL-6 mRNA levels but did not detectably change IL-1 beta or TNF-alpha mRNA levels. In contrast, LPS did not increase
leukemia inhibitory factor
mRNA, which was constitutively expressed and not significantly reduced by these inhibitors. In addition to cytokine mRNA levels, LPS-induced IL-6 protein synthesis and IL-6 bioactivity were also reduced to baseline levels by the PTK inhibitors herbimycin A and genistein. Both PTK inhibitors also reduced the LPS activation of nuclear factor-kappa B (NF-kappa B), which is a transcription factor involved in the expression of cytokine genes such as IL-6 and TNF-alpha. The activation of NF-kappa B was also reduced by H89, whereas staurosporine had no effect on this response. In summary, these findings suggest that protein kinase C and
protein kinase A
appear to have selective effects in the LPS induction of cytokines, whereas PTK is required for LPS induction of a broad spectrum of cytokines and NF-kappa B activation in monocytes.
...
PMID:Protein tyrosine kinase activation is required for lipopolysaccharide induction of cytokines in human blood monocytes. 825 85
Bone-resorbing osteoclasts are of hemopoietic cell origin, probably of the CFU-M-derived monocyte-macrophage family. Bone marrow-derived osteoblastic stromal cells play an important role in modulating the differentiation of osteoclast progenitors in two different ways: one is the production of soluble factors, and the other is cell-to-cell recognition between osteoclast progenitors and osteoblastic stromal cells. M-CSF is probably the most important soluble factor, which appears to be necessary for not only proliferation of osteoclast progenitors, but also differentiation into mature osteoclasts and their survival. A number of local factors as well as systemic hormones induce osteoclast differentiation. They are classified into three categories in terms of the signal transduction: vitamin D receptor-mediated signals [1 alpha,25(OH)2D3];
protein kinase A
-mediated signals (PTH, PTHrP, PGE2, and IL-1); and gp130-mediated signals (IL-6, IL-11, oncostatin M, and
leukemia inhibitory factor
). All of these osteoclast-inducing factors appear to act on osteoblastic cells to commonly induce osteoclast differentiation factor (ODF), which recognizes osteoclast progenitors and prepares them to differentiate into mature osteoclasts. This line of approach will undoubtedly produce new ways to treat several metabolic bone diseases caused by abnormal osteoclast recruitment such as osteoporosis, osteopetrosis, Paget's disease, rheumatoid arthritis, and periodontal disease.
...
PMID:Modulation of osteoclast differentiation by local factors. 857 4
Axotomy of sympathetic superior cervical ganglia (SCG) causes Schwann cells to induce mRNA encoding leukemia inhibitory factor (LIF), a neuropoietic cytokine that has been shown to promote sympathetic neuron survival and peptide gene regulation.
LIF
mRNA is virtually undetectable in uninjured SCG, but is induced by the inflammatory cytokine interleukin-1 (IL-1). The SC1 Schwann cell line was used to study this regulatory mechanism.
LIF
mRNA increased five-to-tenfold in SC1 cells when IL-1 receptors were stimulated with IL-1. The action of IL-1 is thought to be mediated by the type I IL-1 receptor (IL-1RI), which has been suggested to stimulate a ceramide-dependent
protein kinase
pathway, much like tumor necrosis factor-alpha. However, stimulation of the ceramide-dependent
protein kinase
pathways in SC1 cells with either 2-acetylceramide or sphingomyelinase treatment does not induce
LIF
mRNA accumulation, but 2-acetylceramide addition induces cyclooxygenase-2 mRNA in parallel experiments. Inhibition of phosphotidylcholine-phospholipase C activity, endosomal acidification, or activity of atypical protein kinase C reduce
LIF
induction by IL-1. These results are consistent with IL-1 regulation of
LIF
mRNA through stimulation of the endosomal, acidic sphingomyelinase pathway, leading to ceramide activation of protein kinase C zeta. Utilization of this branch of the ceramide signaling pathway may be cell type specific or may be specific for the
LIF
mRNA response.
...
PMID:Activation of acidic sphingomyelinase and protein kinase C zeta is required for IL-1 induction of LIF mRNA in a Schwann cell line. 889 91
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