Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The interferons (IFNs) have been shown to be antagonistic to the growth stimulatory effects of mitogens on cultured cells. A report of the interactions of IFN-beta and platelet-derived growth factor on BALB/c-3T3 mouse cells established that IFN itself induced the secretion of a limited number of proteins from this cell line. The present work was undertaken to determine if other murine cell lines treated with homologous IFN-beta also secreted new or additional protein(s) in response to this agent and if this response correlated with other phenotypic properties of the cells. The cell lines examined included L929 cells and two derivatives of this line (GM347 and WDIFN), CAK-TK-, Swiss-3T3, and BALB/c-3T3. Each line was exposed to [35S]methionine in the absence and in the presence of IFN-beta, the supernatant fluids collected, and the radioactive, secreted proteins examined by fluorography after electrophoresis through SDS-containing polyacrylamide gels. Two cell lines (GM347 and Swiss-3T3) did not appear to secrete new or additional proteins after IFN treatment. However, four lines (L929, WDIFN, CAK-TK-, and BALB/c-3T3) did secrete new or additional proteins in response to IFN. Thus IFN-induced secretion of protein appeared to be a common but not universal phenomenon. In addition, although the number and apparent size(s) of the IFN-induced, secreted proteins were different in these various lines, one protein (Mr = 89-90,000) appeared to be secreted by each of them. In this respect it was unique. Moreover the IFN-induced secretion of protein did not appear to correlate with the antiviral or antiproliferative effects of IFN.
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PMID:Effect of interferon on secretion of proteins by various murine cell lines. 245 71

Human lymphocytes obtained by cytapheresis were stimulated in spinner culture conditions by nonpurified PHA in order to study the production of gamma interferon, and the characterization of IFN-gamma mRNA. Titers of interferon prepared in 0.6 to 4 1 batches, varied in 20 preparations from 8,000 to 32,000 units/ml. This interferon was unstable at pH 2: the residual antiviral activity after 20 h treatment was less than 3%. Antibodies raised against gamma interferon from Con A and SEA-stimulated lymphocytes neutralized the interferon induced by PHA, indicating that all three preparations are antigenically related. Poly(A)RNA from control, noncultivated lymphocytes and from lymphocytes stimulated by PHA for 18 h were translated in reticulocyte lysates and analysed by polyacrylamide gel electrophoresis. The pattern of synthesized polypeptides was different suggesting modifications in the population of mRNA. When total poly(A)RNA was inoculated into Xenopus Laevis oocytes, interferon activity was found with both, control and stimulated mRNAs although only at low levels in the control. After sucrose gradient fractionation of poly(A)RNA, each fraction was inoculated into oocytes and interferon activity measured in the oocyte bathing medium. A low level was synthesized by the RNA fractions around 28 S from control as well as from stimulated lymphocytes. These interferons were not neutralized by anti-IFN-alpha or anti-IFN-gamma sera but they were neutralized by anti-IFN-beta serum. Only the 16 S RNA fraction from PHA-stimulated lymphocytes induced high levels of interferon in oocytes. This interferon has been characterized as gamma interferon. Each fraction obtained from sucrose gradients on poly(A)RNA from control and PHA-stimulated lymphocytes was translated in reticulocyte lysate. Gel analysis of the products showed striking differences when the same fraction of both RNAs were compared. Concerning particularly the 16 S RNA from PHA-stimulated lymphocytes, where gamma interferon mRNA was present, polypeptides ranged from 15 to 55 K with a bulk around 45 K, indicating heterogeneous RNA molecules.
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PMID:Translation of mRNA from phytohemagglutinin-stimulated human lymphocytes: characterization of interferon mRNAs. 612 11

We previously demonstrated that the gene tyk2 rescues the phenotype of a human mutant cell line unresponsive to alpha (IFN) and partially responsive to IFN-beta. Here, we describe functional complementation of the mutant cells with the corresponding cDNA. To characterize the putative non-receptor protein tyrosine kinase encoded by the gene tyk2 and begin to understand its functioning, we have raised polyclonal antibodies against a segment of the protein. Using these, we have identified tyk2 as a 134-kDa protein which is rapidly and transiently phosphorylated on tyrosine in response to IFN-alpha/beta and possesses an inducible kinase activity when tested in vitro. IFN-gamma has no effect on the phosphorylation state of the protein. In agreement with previous genetic evidence, these results assign a role to tyk2 in the IFN-alpha/beta signalling pathway and not in the IFN-gamma pathway. Fractionation of cell lysates have helped to localize the bulk of the protein in the cytoplasm, with a minor fraction associated with the cell membrane. Both protein pools undergo activation upon short-term IFN treatment of intact cells. Through the study of the effect of pervanadate on the phosphorylation level and the activity of tyk2, we conclude that activation of tyk2 by IFN-alpha does not require an intermediate regulatory tyrosine phosphatase.
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PMID:Activation of the protein tyrosine kinase tyk2 by interferon alpha/beta. 805 12

It is well known that interferon-gamma (IFN-gamma; type II) potentiates various responses of human tumor necrosis factor (TNF) in a wide variety of cells and that this potentiation is accompanied by the up-regulation of TNF receptor synthesis. In the present studies we examined the regulation of TNF receptors by type I and type II IFNs in a hepatocellular carcinoma cell line, HEP G2. Exposure of these cells to IFN-gamma led to a decrease in TNF receptor number (4029 vs. 2719 sites/cell) without any change in the receptor affinity (0.96 nM vs. 1.1 nM). The effect was time and dose-dependent. Like IFN-gamma, IFN-alpha and IFN-beta (type I) down-modulated the TNF receptors on these cells. The effect of IFNs on the TNF receptors was inhibited by staurosporin, a protein kinase C (PK-C) inhibitor. Furthermore, by the use of receptor-specific antibodies, we found that the IFN-dependent decrease was primarily due to the p60 form of the TNF receptor. Our results presented are the first to demonstrate that IFNs can also down-modulate TNF receptors in certain cells and that this effect is mediated through PK-C.
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PMID:Both type I and type II interferons down-regulate human tumor necrosis factor receptors in human hepatocellular carcinoma cell line Hep G2. Role of protein kinase C. 827 22

Monocytes-macrophages which serve as host immune cells to kill pathogens can often be "activated" after exposing to viruses, bacteria, cytokines as well as chemical substances, However, it is paradoxical that highly activated macrophages can be induced to become the suppressor ones by live microbes, microbial products, tumor, and autoimmune disease, although the mechanism remains unknown. Our previous experimental studies have shown that immuno-suppressor activities of suppressor macrophages on T, B and NK cells can be prevented by the treatment with LPS or supernatant in vitro from mitogen-stimulated lymphocytes, while, at the same time, the tumoricidal activities of those macrophages can be kept or even enhanced following the same treatment. This phenomenon was then termed as "immune modulation" For the understanding of its mechanism, we are now undertaking signal transduction in modulated macrophages. Since mitogen-activated protein kinase (MAPK) is an integration point of different signal transduction pathways, its cascade and regulation of activation are being investigated extensively by the assay of electrophoresis mobility shift. Recent results suggested that interaction of ligand-receptor triggers protein tyrosine kinase(PTK) activation leading to Ras-GTP binding with Raf-1 to phosphorylate MAPK kinase (MAPKK), the specific activator of MAPK. It is reported that PKC-alpha can directly phosphorylate or activate Raf-1 in NIH3 T3 cells. Raf-1 (74 KDa), with an intrinsic serine (Ser)-threonine (The) kinase activity, becomes hyperphosphorylated after activation which can be followed by gel mobility shift test. It has also been shown that a variety of extracellular factors stimulate a pair of MAPK p44 and MAPK p42 of MAPK family members. A significant property of activation of ERK 1 and ERK 2 is the requirement for the phosphorylation of both Thr-183 and Tyr-185 (at TEY motif) within in its protein kinase subdomain VIII. More recently, two other MAPK subtypes, p38 MAPK (mammalian equivalents of HOG1 in yeast) and JNK MAPK have been discovered. The requirement for activation of p38 MAPK for both Thr-180 and Tyr-182 (at TGY motif) has been shown. p38 MAPK is important in certain transcriptional regulatory pathways, since it can phosphorylate the following transcriptional factors: 1) Elk at Ser 383/389 for binding with SRE motif; 2). ATF 2 at Ser 69/71, forming a complex with Myc for DNA binding at CRE motif; 3) Max at Ser-62 to combine DNA of E-Box motif. p38 MAPK can be activated by LPS, inflammatory cytokines, such as TNF and IL-1, osmolarity. To examine the possibility that whether activation of Raf-1 and ERK 1, ERK2 and p38 MAPK can be regulated directly or/and differently by PKC and PKA pathways, herbimycin A (Ki = 0.9 mumol/L), a potent PTK inhibitor (J. Immunol. 155:3944-4003, 1995) at 2 mumol/L concentration was utilized to block Ras/Raf-1/MAPK cascade. After pre-incubation of macrophages with herbimycin A for 30 min or 90 min, cells were treated with LPS (10 micrograms/ml) and PMA (100 nmol/L) for 15 min. No inhibition of phosphorylation of Raf-1, MAPK p44 and MAPK p42 in response to LPS and PMA was observed (Fig. 1 and 3). However, forskolin, a cAMP inducer for protein kinase A (PKA) activation, inhibited the phosphorylation of LPS- and PMA-stimulated Raf-1, MAPK p44 and MAPK p42 (Fig. 2 and 4). Similarly, in agreement with a very recent report from David, M et al in NIH, in which they indicated that forskolin (30 mumol/L) inhibited IFN-beta-stimulated ERK activity by U 266 cells (J. Biol. Chem. 271: 4585-4588 1996), we found that the levels of phosphorylations of Raf-1 and ERK1 and ERK2 were declined when forskolin (30 mumol/L) was added to macrophages for 20 min at 37 degrees C prior to the stimulation by LPS and PMA. Interestingly, under the same condition, forskolin (30 mumol/L) stimulated the phosphorylation of LPS- and PMA-triggered p38 MAPK of murine peritoneal suppressor macrophages, suggesting that activatio
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PMID:[Studies on cell signaling immunomodulated murine peritoneal suppressor macrophages: LPS and PMA mediate the activation of RAF-1, MAPK p44 and MAPK p42 and p38 MAPK]. 1068 11

Continuous human leukemia-lymphoma (LL) cell lines represent a rich resource of abundant, accessible and manipulable living cells contributing significantly to a better understanding of the pathophysiology of hematopoietic tumors. In particular, classical and molecular cytogenetics have benefitted enormously from the availability of LL cell lines with specific chromosomal abnormalities. Such aberrations may be the portal to the discovery of novel oncogene rearrangements for which positive cell lines provide a resource for both discovery and functional studies. The new continuous leukemia cell line MUTZ-11 was established in 1994 from the peripheral blood of a 60-year-old woman with acute myeloid leukemia (AML) M4 (following 2 years with myelodysplastic syndromes). DNA fingerprinting confirmed the authenticity and derivation of the cell line. The immunoprofile as determined by flow cytometry was as follows: positive for myelocytic markers (CD13, CD15, CD33, CD65 and CD68), negative for T-cell (except for CD4 and CD7), B-cell and erythroid-megakaryocytic markers. The cell line is constitutively cytokine-dependent and growth depends on externally added cytokines. With regard to cytokine receptor expression, the cell line was found to be positive for GM-CSFRalpha (granulocyte-macrophage colony-stimulating factor receptor, CD116), Kit (CD117) and IL-3Ralpha (interleukin-3 receptor, CD123). The cytokine response profiles as determined by [(3)H]-thymidine incorporation assay were: 2-to-12 fold growth stimulation of MUTZ-11 by GM-CSF, IFN-alpha (interferon), IFN-beta, IFN-gamma, IL-3 and SCF (stem cell factor); growth inhibition by TGF-beta1 (transforming growth factor), TNF-alpha (tumor necrosis factor) and TNF-beta. Cytogenetic analysis showed the following consensus karyotype: 46, XX, der(16)t(16;17)(p13.3;q23)x2. Previous molecular biological analysis documented that MUTZ-11 cells carry both an FLT3 internal tandem duplication (ITD) and an MLL partial tandem duplication (PTD). The scientific significance of MUTZ-11 lies (i). in the absolute cytokine-dependency and the proliferative response to various cytokines, (ii). in the unique cytogenetic (disomic t(16;17)) and (iii). molecular biological alterations (FLT3 ITD + MLL PTD). In summary, the new cytokine-dependent AML-derived cell line MUTZ-11 displays unique novel features and emphasizes the need for comprehensive analysis of new LL cell lines which may lead to the discovery of important pathogenetic alterations.
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PMID:New cytokine-dependent acute myeloid leukemia cell line MUTZ-11 with disomic chromosome rearrangement t(16;17). 1506 4

In this study we compared the activation of monocytes by different bacterial products via Toll-like receptors (TLR), and by different proinflammatory mediators. In response to TLR-2, -4 and -5 engagement, approximately 50% of monocytes produced TNF-alpha, compared to only 5% after induction with IFN-gamma or GM-CSF. Furthermore, a small proportion of monocytes produced IL-10 after stimulation via TLR, but not after stimulation with cytokines. Both TLR-ligands and inflammatory cytokines induced the expression of CD25, CD69, CD80 and, surprisingly, also of CD83, commonly regarded as an activation marker for mature dendritic cells (DC). Conversely, TLR-ligands downregulated CD38, CD86 and ICOS-L. Importantly, signaling lymphocytic activation molecule (SLAM; CD150) was identified as a monocyte activation marker that could be induced ex novo via TLR-2, -4 and -5, but not by single stimulation with monocyte activators like IL-1, TNF-alpha, IFN-beta, IFN-gamma, GM-CSF or CD40-L. SLAM expression was transient and required mitogen activated protein kinase (MAPK) p38, but not ERK or JNK, and was surprisingly independent of NF-kappaB. SLAM+ monocytes, which are absent in blood, were detected in spleen and tonsils, where they could be localized to T-cell areas and germinal centers. Together, by comparing the response of monocytes to TLR-ligands and inflammatory cytokines, we have identified a monocyte activation marker, SLAM, which differs in its inducibility from other monocyte activation markers. SLAM+ monocytes and macrophages were identified for the first time in vivo. Their presence might be a sign of innate immune activation.
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PMID:Distinct responses of monocytes to Toll-like receptor ligands and inflammatory cytokines. 1509 75

Theiler's murine encephalomyelitis virus (TMEV) infection of macrophages induces a demyelinating disease (DD) in certain strains of mice that is similar to human multiple sclerosis. In contrast to IFN-beta, expression of IL-23 p19 and p40 subunits by macrophages in response to TMEV may contribute to DD. TMEV infection of macrophages likely induces IL-23 and IFN-beta by activating p38 or ERK MAP-kinases (MAPK) and the p38 substrate ATF-2 within 30 min. To determine the role of MAPKs in TMEV-induced IL-23 and IFN-beta expression, RAW264.7 cells were pretreated with SB203580 or U0126, inhibitors of p38 and ERK MAPKs, respectively. SB203580 significantly increased TMEV-induced p19 but decreased p40 expression. In contrast, U0126 decreased p19 and increased TMEV-induced p40 and IFN-beta expression. Interestingly, U0126 prolonged TMEV-induced ATF-2 activation to at least 3h. Thus ERK MAPKs regulate expression of TMEV-induced p19 differently than p40 and IFN-beta suggesting the benefits of U0126 in treatment of DD.
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PMID:ERK-MAP-kinases differentially regulate expression of IL-23 p19 compared with p40 and IFN-beta in Theiler's virus-infected RAW264.7 cells. 1562 75

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.
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PMID:RANKing intracellular signaling in osteoclasts. 1601 47

IFN-alpha controls hormone secretion and symptoms in human gastroenteropancreatic neuroendocrine tumors (GEP-NET) but it rarely induces a measurable tumor size reduction. The effect of other type I IFNs, e.g., IFN-beta, has not been evaluated. We compared the antitumor effects of IFN-alpha and IFN-beta in BON cells, a functioning human GEP-NET cell line. As determined by quantitative reverse transcription-PCR analysis and immunocytochemistry, BON cells expressed the active type I IFN receptor mRNA and protein (IFNAR-1 and IFNAR-2c subunits). After 3 and 6 days of treatment, IFN-beta significantly inhibited BON cell growth in a time- and dose-dependent manner. IC50 and maximal inhibitory effect on day 6 were 8 IU/mL and 98%, respectively. In contrast, the effect of IFN-alpha resulted significantly in a less potent effect (IC50: 44 IU/mL, maximal inhibition: 26%). IFN-alpha induced only cell cycle arrest, with an accumulation of the cells in S phase. IFN-beta, apart from a more potent delay in S-G2-M phase transit of the cell cycle, also induced a strong stimulation of apoptosis, evaluated by flow cytometry (Annexin V and 7-AAD) and measurement of the DNA fragmentation. Besides, only IFN-beta severely suppressed chromogranin A levels in the medium from BON cells after 6 days of treatment. In conclusion, IFN-beta is much more potent, compared with IFN-alpha, in its inhibitory effect on GEP-NET cell proliferation in vitro through the induction of apoptosis and cell cycle arrest. Further studies are required to establish whether IFN-beta has comparable potent tumor growth inhibitory effects in vivo.
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PMID:IFN-beta is a highly potent inhibitor of gastroenteropancreatic neuroendocrine tumor cell growth in vitro. 1639 72


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