Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

At weaning the mammary gland undergoes a reductive remodelling process (involution) which is associated with the cessation of milk protein gene expression and programmed cell death of milk-producing epithelial cells. Elevated nuclear protein kinase A (PKA) activity was observed from one day post-lactation, paralleled by increased c-fos, junB, junD and to a lesser extent c-jun mRNA levels. AP-1 DNA binding activity was transiently induced and the AP-1 complex was shown to consist principally of cFos/JunD. Oct-1 DNA binding activity and Oct-1 protein were gradually lost from the gland over the first 4 days of involution, whereas Oct-1 mRNA levels remained unchanged. Comparing nuclear extracts from normal mammary glands with nuclear extracts from glands which had been cleared of all epithelial cells 3 weeks after birth, revealed that PKA activation, AP-1 induction and Oct-1 inactivation all are dependent on the presence of the epithelial compartment. The increased Fos/Jun expression and the inactivation of Oct-1 may be consequences of the increased PKA activity. A similar induction of AP-1 (cFos/JunD) was also observed in the involuting rat ventral prostate pointing to a possible role for AP-1 in programmed cell death.
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PMID:Protein kinase A and AP-1 (c-Fos/JunD) are induced during apoptosis of mouse mammary epithelial cells. 813 24

Interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) have previously been reported to induce rapid phosphorylation of the mitogen-activated protein (MAP) kinase. However, little is known about signaling events initiated by both hematopoietins that occur downstream of the MAP kinase. MAP kinase has been shown to phosphorylate the AP-1 transcription factor and also to activate two kinases designated insulin-stimulated protein kinase-1 and MAP kinase-activated protein (MAP-KAP) kinase 2. We show here that IL-3 and GM-CSF induce MAPKAP kinase 2 activity in the human megakaryoblastic leukemia cell line MO7 and phosphorylate the human small heat shock protein Hsp 27 on serine residues in vitro. GM-CSF also induced Hsp 27 phosphorylation in neutrophils in a range similar to that observed in MO7 cells, suggesting that MAPKAP kinase 2-mediated Hsp 27 activation occurs independently of proliferation. Hsp 27 phosphorylation was dose-dependent, occurred as early as 5 minutes after factor exposure, and was inhibited by the tyrosine kinase inhibitors genistein and herbimycin A. Furthermore, the protein phosphatase A2 abolished IL-3- and GM-CSF-induced serine phosphorylation of Hsp 27. Taken together, our findings indicate that tyrosine phosphorylation of MAP kinase is a prerequisite for serine phosphorylation of Hsp 27, which is mediated by MAPKAP kinase 2. Hsp 27 has shown activation-dependent translocation from the cytosolic to the nuclear region and has been linked to the cellular stress response. However, its precise function is largely unknown. Our data identify Hsp 27 as a target of the IL-3/GM-CSF stimulation pathway that involves MAP kinase and MAPKAP kinase 2. In addition, our results indicate that Hsp 27 may be target of phosphorylation events not only in the stress response but also in unstressed cells responding to cytokine stimulation.
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PMID:Interleukin-3 and granulocyte-macrophage colony-stimulating factor induce activation of the MAPKAP kinase 2 resulting in in vitro serine phosphorylation of the small heat shock protein (Hsp 27). 1101 49

The most potent, physiologic activator of proopiomelanocortin (POMC) gene transcription is corticotropin releasing hormone (CRH) and increased intracellular cAMP is critical for this effect. The 5'-flanking region of the murine POMC gene has several potential binding sites for regulatory proteins. To characterize the region between nucleotides -141 and -106, which includes a TRE-like site and an adjacent AP-2 consensus sequence, and to study its role in signal-transcription coupling, gel mobility shift assays and transient expression of CAT chimeras were performed. In transient transfections of AtT-20 cells with pCATp-141/-106, CRH treatment led to significant increases in CAT expression compared with CRH treatment of cells transfected with the enhancerless vector. However, no response to direct activation of cAMP dependent protein kinase or protein kinase C was detected. Despite the high homology of the sequence -137/-131 to the consensus AP-1 binding site (TRE), the nuclear factor(s) in AtT-20 cells binding to this region appears to be different than authentic AP-1 since neither a competitor oligonucleotide having the authentic TRE sequence nor antibodies against Jun or Fos affected the gel shift pattern of a probe having the -137/-131 sequence. We conclude that the -141 to -106 region of the murine POMC gene contains a functional CRH responsive element and that second messenger systems that transduce the CRH signal to this element do not exert their actions solely through activation of PKA or PKC.
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PMID:Characterization of a corticotropin releasing hormone responsive region in the murine proopiomelanocortin gene. 814

The involvement of protein kinase C (PKC), a 12-O-tetradecanoylphorbol-13-acetate (TPA) receptor, in the transcriptional regulation of TPA-inducible genes was determined. Expression plasmids harboring full-length or kinase domain of PKC alpha and PKC delta (PKC alpha K and PKC delta K) were constructed. Transient transfection of PKC alpha K and PKC delta K into COS cells resulted in approximately 20- and 16-fold increase in phospholipid-, calcium-independent protein kinase activity. To determine the effects of overexpression of PKC alpha K and PKC delta K on the AP-1-mediated TPA-inducible genes, we transfected into COS cells the PKC alpha K or PKC delta K expression plasmids with collagenase chloramphenicol acetyltransferase (CAT) reporter construct containing one TPA responsive element (TRE), or a construct containing five synthetic TRE linked to a thymidine kinase promoter. PKC alpha K or PKC delta K overexpression resulted in a comparable increase (approximately 4-fold) in CAT activity. However, CAT activity was not increased after transfection of PKC constructs with non-TPA responsive thyroid hormone responsive elements CAT construct (delta MTV-TyRE-pCAT). We also found that deletion of the AP-1-like motif in the SV40 promoter abolished the PKC alpha K or PKC delta K-induced activity of luciferase (luc) reporter constructs. Overexpression of full-length PKC delta in COS cells also increased the activity of the CAT construct with TRE after TPA treatment. We determined the effects of overexpression of PKC alpha K and PKC delta K on transcription of the ornithine decarboxylase (ODC) gene, which has a non-AP-1 TRE. Cotransfection of PKC alpha K or PKC delta K expression plasmids with a TPA-inducible ODC luc construct (-72/+130-ODC-luc) into HeLa cells resulted in an increased luc activity. These results indicate that both PKC alpha (calcium dependent) and PKC delta (calcium independent) may mediate the transcription of TPA-inducible genes through both AP-1 and non-AP-1 sequences.
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PMID:Involvement of protein kinase C in the transcriptional regulation of 12-O-tetradecanoylphorbol-13-acetate-inducible genes modulated by AP-1 or non-AP-1 transacting factors. 814 84

Activating transcription factor-3 (ATF-3) is one member of a large family of leucine zipper transcription factors which bind to promoters responsive to cAMP and phorbol ester at the related cAMP (CRE) and phorbol ester response elements. We report here that ATF-3 is coexpressed with the neuropeptide precursor proenkephalin in human neuroblastoma SK-N-MC cells. Cotransfection experiments indicate that activation of proenkephalin gene expression by ATF-3 is dependent upon both the catalytic subunit of the cAMP-dependent protein kinase and the CRE-2 element. The CRE-2 element is essential for second messenger-inducible expression and is known to bind AP-1-like transcription factors. ATF-3 expressed in bacteria or from rabbit reticulocyte lysates binds to the proenkephalin CRE-2 element as a homodimer and as a heterodimer with Jun-D, another activator of proenkephalin transcription. ATF-3 stimulates binding of Jun-D to the proenkephalin CRE-2 element and acts synergistically with Jun-D to induce proenkephalin gene expression. Sequential immunoprecipitations of ATF-3 from SK-N-MC cells expressing proenkephalin indicate that ATF-3 is complexed with Jun-D in vivo and that both proteins are highly phosphorylated. Together, our results suggest that ATF-3 may play an important role in the regulation of gene expression by cAMP-dependent intracellular signaling pathways.
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PMID:Activating transcription factor-3 stimulates 3',5'-cyclic adenosine monophosphate-dependent gene expression. 815 31

For successful allogenic pregnancy to occur, suppression of maternal defense responses toward the fetus are vital. Suppressor factors elaborated by decidual cells or immune cells may facilitate this suppression. In order for appropriate cellular responses to occur an intact signal transduction/second messenger system must be present. The calcium/phospholipid-dependent protein kinase, Pk-C, plays an important role in regulating immune responses, and may also be important in regulating uterine cell responses and implantation events. Pk-C activation is necessary for IL-2 synthesis and IL-2 receptor synthesis through activation of the proto-oncogenes c-jun and c-fos. These proto-oncogene gene products combine to form the heterodimer AP-1 which then activates IL-2 gene transcription for both peptide and receptor. If Pk-C activity becomes abrogated then appropriate cell responsiveness is diminished. We have shown that Pk-C activity is decreased in the particulate fraction of 4-7 day pregnant spleen, thymus and draining lymph node (DLN) cells. Spleen cells did not exhibit any change in cytosolic Pk-C activity, the thymus was found to have a decrease in both cytosol and particulate fractions, and the DLN cells exhibited a translocation effect whereby particulate Pk-C decreased and cytosolic Pk-C activity increased. Supernatant from 3-day cultures of DLN cells from pregnant animals was shown to inhibit proliferation of spleen cells. In addition, the supernatant was able to directly lower Pk-C activity. We hypothesize that DLN cells secrete a factor(s) that is able to suppress immune response through abrogation of Pk-C activity, thereby decreasing AP-1 formation resulting in decreased IL-2 synthesis and IL-2 receptor synthesis.
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PMID:Pregnancy-associated, lymphocyte-derived suppressor factor inhibits protein kinase C activity. 822 96

AP50 is a subunit of the assembly polypeptide (AP) subclass AP-2 from bovine brain coated vesicles. It can be phosphorylated in vivo and in vitro on a threonine residue by means of the AP50 kinase activity associated with AP. We have undertaken an analysis of the amino acid sequence around the AP50 phosphorylation site. After phosphorylation in vitro of AP50 followed by tryptic cleavage, only one radioactive peptide was isolated following Mono-Q ion-exchange f.p.l.c. and reverse-phase h.p.l.c. The amino acid sequence of this peptide: Glu146-Glu-Gln-Ser-Gln-Ile-Thr-Ser-Gln-Val-Thr*-Gly-Gly-Ile-Gly-Tr p-Arg162, displayed two threonine residues. Analysis of the yield and radioactivity of the product from automated Edman degradation indicated that only Thr-156 was phosphorylated, reflecting the presence of a single phosphorylation site in AP50. AP phosphorylated the corresponding synthetic peptide on the same threonyl residue. We demonstrated that AP50 was a phosphorylation substrate unable to autophosphorylate. The enzyme involved in the AP50 phosphorylation was shown to be associated with AP-1 and with a soluble protein complex co-purified with APs but resolved from the latter by hydroxyapatite-column exclusion chromatography. This AP50 kinase activity corresponded to a 280 kDa protein complex according to gel-filtration data.
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PMID:The 50 kDa protein subunit of assembly polypeptide (AP) AP-2 adaptor from clathrin-coated vesicles is phosphorylated on threonine-156 by AP-1 and a soluble AP50 kinase which co-purifies with the assembly polypeptides. 825 32

AP-1 is a transcriptional activator composed of homo- and heterodimers of Jun and Fos proteins. It is involved in activation of genes, such as collagenase, stromelysin, IL-2 and TGF beta 1, by tumour promoters, growth factors and cytokines. AP-1 activity is also elevated in response to transforming oncogenes and is required for cell proliferation. AP-1 activity is subject to complex regulation both transcriptionally and post-transcriptionally. Transcriptional control of jun and fos gene expression determines the amount and composition of the AP-1 complex. The jun and fos genes are regulated both positively and negatively and are highly inducible in response to extracellular stimuli. Post translational control is also important. Both cJun and cFos are subject to regulated phosphorylation. In the case of cJun, phosphorylation of sites near the DNA-binding domain inhibits DNA-binding, while dephosphorylation reverses this inhibition. Phosphorylation of cJun on sites within the N-terminal activation domain increases its ability to activate transcription. The protein kinase phosphorylating these sites is stimulated by cytokines and growth factors. Another mechanism modulating AP-1 activity is transcriptional interference by members of the nuclear receptor family and is relevant for the pathophysiology of rheumatoid arthritis (RA). In RA, chronic inflammation leads to increased AP-1 activity in T cells,macrophages and synoviocytes as a response to secretion of cytokines such as IL-1 and TNF alpha. While the IL-2 gene plays a major role in T cell activation, another AP-1 target gene encodes an enzyme, collagenase, responsible for destruction of bone and tendon.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Various modes of gene regulation by nuclear receptors for steroid and thyroid hormones. 831 34

Fos and Jun form dimeric complexes that bind to activator protein 1 (AP-1) DNA sequences and regulate gene expression. The levels of expression and activities of these proteins are regulated by a variety of extracellular stimuli. They are thought to function in nuclear signal transduction processes in many different cell types. The role of Fos and Jun in gene transcription is complex and may be regulated in several ways including association with different dimerization partners, interactions with other transcriptional factors, effects on DNA topology, and reduction/oxidation of a conserved cysteine residue in the DNA-binding domain. In addition, phosphorylation has been suggested to control the activity of Fos and Jun. Here we show that phosphorylation of Fos and Jun by several protein kinases is affected by dimerization and binding to DNA. Jun homodimers are phosphorylated efficiently by casein kinase II, whereas Fos-Jun heterodimers are not. DNA binding also reduces phosphorylation of Jun by casein kinase II, p34cdc2 (cdc2) kinase, and protein kinase C. Phosphorylation of Fos by cAMP-dependent protein kinase and cdc2 is relatively insensitive to dimerization and DNA binding, whereas phosphorylation of Fos and Jun by DNA-dependent protein kinase is dramatically stimulated by binding to the AP-1 site. These results imply that different protein kinases can distinguish among Fos and Jun proteins in the form of monomers, homodimers, and heterodimers and between DNA-bound and non-DNA-bound proteins. Thus, potentially, these different states of Fos and Jun can be recognized and regulated independently by phosphorylation.
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PMID:Dimerization and DNA binding alter phosphorylation of Fos and Jun. 834 96

Urokinase-type plasminogen activator (uPA) is an extracellular protease and expressed in various cells that exhibit dynamic changes in cell morphology, suggesting a link between cytoskeletal reorganization (CSR) and uPA expression. CSR can be induced by pharmacological agents, such as by colchicine for microtubule cytoskeleton and by cytochalasin for microfilament cytoskeleton. Using these agents, we previously showed that CSR induced the uPA gene in LLC-PK1 cells independently of the protein kinase C and cAMP-dependent protein kinase. Here we show that the induction of the uPA gene by CSR is mediated by the activation of c-Jun which interacts with an AP-1-like site located 2 kb upstream of the uPA gene. 12-O-tetradecanoylphorbol 13-acetate (TPA) induces the uPA gene through the same elements, but additionally utilizes an adjacent PEA3 element and induces c-fos. Furthermore, CSR induces a greater accumulation and a more pronounced phosphorylation of c-Jun than TPA induction. AP-1 is a positive regulator of growth and oncogenesis, and CSR is an integral part of these processes. Our results provide a view how CSR and AP-1 could be coupled in these processes. We also show that TPA and CSR act synergistically, suggesting a model where an initial activation signal could be amplified by CSR.
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PMID:Cytoskeletal reorganization and TPA differently modify AP-1 to induce the urokinase-type plasminogen activator gene in LLC-PK1 cells. 834 15


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