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)

Recently, the SRC-like non-receptor protein tyrosine kinase p56-LCK has been shown to physically associate with the interleukin-2 receptor (IL-2-R) complex and to undergo rapid elevations in its tyrosine kinase activity upon stimulation of T lymphocytes with IL-2. The functional significance of p56-LCK kinase activation for IL-2-mediated lymphocyte responses, however, has never been directly assessed. Using gene transfer approaches, we have achieved markedly elevated levels of p56-LCK kinase activity in the IL-2-dependent cytolytic T-cell line CTLL-2 and the helper line HT-2. CTLL-2 and HT-2 cells that were stably transfected with expression plasmids encoding either the normal human p56-LCK or a constitutively active version of the mouse p56-LCK kinase (LCK[Y505]) contained striking elevations in the levels of tyrosine phosphorylation on several proteins (34-36, 50-60, 62-68, 77-78, 104-110 kDa), as determined by immunoblot analysis using anti-phosphotyrosine antibodies. CTLL-2 and HT-2 LCK- and LCK(Y505F)-transfected cells remained dependent on IL-2 for their growth and survival in culture despite the findings that (i) IL-2 specifically stimulated elevations in the activity of the endogenous p56-LCK in untransfected CTLL-2 cells without affecting the activities of the other SRC-like kinases in these cells (p59-FYN, p62-YES) and that (ii) IL-2-mediated regulation of p56-LCK correlated with IL-2-driven proliferation of these T cells. Specifically, no elevation in the proliferation (DNA synthesis) or growth of these T cells was found at any of the concentrations of IL-2 examined (0.01-25 U/ml), relative to untransfected and control transfected cells. Furthermore, when cultured in the absence of IL-2, transfected T cells whose relative levels of p56-LCK activity were elevated by approximately 20-50-fold died with the same kinetics as control cells and underwent apoptosis, as defined by uptake of trypan blue dye and DNA fragmentation assays, respectively. Taken together, these data indicate that while IL-2 can up-regulate the enzymatic activity of p56-LCK, elevated levels of p56-LCK tyrosine kinase activity are insufficient to stimulate IL-2-mediated pathways required for T-cell growth and survival. These findings thus imply the existence of other signal-transducing molecules, besides p56-LCK, that physically participate in IL-2R complexes and that are necessary for initiation of the biochemical events ultimately responsible for IL-2's pleiotropic actions on lymphocytes.
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PMID:Gene transfer investigations of p56-LCK function in IL-2-dependent T-cell lines: implications for mechanisms of IL-2-signal transduction. 129 28

The expression of 10 protooncogenes has been quantitatively studied in liver of male rats L10 age of 1, 10.5, 22 and 37 months. It was shown that a number of specific mRNA transcripts and, therefore, the levels of expression of protooncogenes C-MYC, C-FOS, N-MYC, HA-RAS, KI-RAS, SIS, ABL, YES, MOS and MET in rat liver were constant during life span. These data are in accordance with resistance of the rat strain L10 to spontaneous hepatocarcinogenesis.
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PMID:[Proto-oncogene expression in the liver of male rats of different age]. 171 16

The expression of protein-tyrosine kinases (PTKs; ATP:protein-tyrosine O-phosphotransferase, EC 2.7.1.112) was studied in normal human lung and various tumors by PCR followed by molecular cloning and sequence analysis. Six known PTKs (YES, FGR, LYN, HCK, PDGFB-R, and CSF1-R), as well as two additional members of this enzyme family, were detected in lung. One of the newly discovered sequences appears to represent a group of cytosolic PTKs. The cDNA sequence of the second unknown PTK revealed that it is a fourth member of the fibroblast growth factor receptor family. It was therefore called TKF (tyrosine kinase related to fibroblast growth factor receptor). Among a wide variety of cells and tissues tested, including human lymphocytes and macrophages, TKF was only found expressed in lung. Apart from normal lung, TKF expression could be demonstrated in some tumors of lung origin, but also in malignancies not derived from lung tissues. As fibroblast growth factors are generally involved in a variety of functions such as mitogenesis, angiogenesis, and wound healing, the specific expression of a receptor-related gene in lung only may point to yet another special function of this group of proteins.
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PMID:Two additional protein-tyrosine kinases expressed in human lung: fourth member of the fibroblast growth factor receptor family and an intracellular protein-tyrosine kinase. 172 May 39

Overexpression and amplification of the erbB-2 (neu) is thought to play a major role in mammary cancer. Although studies suggest that Neu is directly involved in the genesis of mammary tumors, the molecular mechanism by which Neu induces tumors is not well understood. Recently, we have demonstrated that the activity of c-Src tyrosine kinase is elevated in Neu-induced mammary tumors and this elevated activity correlates with its capacity to physically associate with Neu. To explore whether other members of the c-Src family are activated in these mammary tumors, we measured the in vitro kinase activity of the c-Yes and Fyn kinases in protein extracts derived from mammary tumor tissue and morphological normal adjacent tissue. These analyses revealed that c-Yes kinase activity was elevated in Neu-induced tumors by comparison to the adjacent tissue. By contrast, no significant activation of the Fyn kinase was noted in these tumors. Activation of c-Yes tyrosine kinase correlated with the capacity of c-Yes to associate with Neu in vivo in lysates derived from primary tumor samples. Studies with Rat.2 fibroblasts overexpressing activated Neu revealed that c-Src requires the presence of tyrosine phosphorylated Neu for its ability to interact with Neu in vivo. Moreover, analyses using radiolabeled c-Yes SH2 fusion protein revealed that this interaction is likely occurring in a direct fashion. Although both c-Src and c-Yes kinase associate with Neu in vivo, a tyrosine phosphorylated protein of 89 kd (p89) was found associated with c-Src but not with c-Yes in cell lysates derived from mammary epithelial cells transformed by either Neu or PyV middle T antigen. Furthermore, this tyrosine phosphorylated protein was not detected in c-Src complexes derived from fibroblasts transformed by either Neu or PyV middle T. These observations suggest that p89 associates with c-Src only in mammary epithelial cells and not in fibroblasts.
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PMID:Activation of Src family kinases in Neu-induced mammary tumors correlates with their association with distinct sets of tyrosine phosphorylated proteins in vivo. 747 8

We have determined the nucleotide sequence and gene map location of the Xiphophorus maculatus homologue of RPS15 (ribosomal protein S15, alias RIG). The Xiphophorus RPS15 cDNA encodes 145 amino acids, which show 94% identity compared to deduced mammalian and avian RPS15 amino acid sequences. At the nucleotide level, 84% sequence identity is maintained between the fish and human gene, while homologous amphibian and avian sequences show about 80% nucleotide identity compared to the Xiphophorus sequence. Nucleotide identity substantially decreases when the fish gene is compared to Arabidopsis S15 (64%) and yeast S21 (55%) genes. Genetic linkage analysis of an RPS15 restriction fragment length polymorphism in backcross hybrids generated from the cross X. helleri x (X. maculatus Jp 163 B x X. helleri) demonstrated linkage of Xiphophorus RPS15 to the EGFR, UMPK and YES loci in Xiphophorus Linkage Group VI.
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PMID:Characterization and mapping of the Xiphophorus maculatus (Teleostei: Poeciliidae) RPS15 gene. 904 Jul 80

Xiphophorus fish have been the subject of intensive genetic research for more than 60 yr, primarily because of the availability of a number of interspecific hybrids that are malignant melanoma models with apparently simple oncogene and tumor suppressor gene determinants. The gene map of Xiphophorus is one of the most extensive among nonhuman vertebrates, with about 100 genes assigned to at least 20 independently assorting linkage groups (LGs), as well as more than 250 anonymous DNA sequence markers, providing coverage for most of the genome for genetic mapping studies. This characteristic has resulted in the mapping of a tumor suppressor locus, DIFF, which is one of two genetic determinants of melanoma formation in the best-studied hybrid melanoma, the Gordon-Kosswig melanoma model. The other gene responsible for melanoma formation in this model is a sex-linked tyrosine kinase gene related to EGFR and called Xiphophorus melanoma receptor kinase (Xmrk). The cellular oncogene homologues of the non-receptor tyrosine kinase family orthologous toyes and fyn have also been found to be overexpressed in malignant melanomas of Xiphophorus and may be involved in tumor progression. We report here the map location of a Xiphophorus yes gene, YES1, in LG VI, closest to the EGFR gene and the assignment of a fyn gene homologue to newly designated LG XV, linked to the gene for cytosolic alpha-galactosidase. We also confirmed that an EGFR-related sequence (EGFRL1) that we previously assigned to Xiphophorus LG VI by cross-hybridization to a viral erbB probe was the EGFR orthologue. Our results suggest that the presence of expressed duplicates of members of the tyrosine kinase gene family in teleost fishes may increase the potential number of targets in oncogenic cascades in fish tumor models.
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PMID:Mapping of tyrosine kinase gene family members in a Xiphophorus melanoma model. 968 40

In this paper, we present evidence that activation of 5-hydroxytryptamine 2B (5-HT2B) receptors by serotonin (5-HT) leads to cell-cycle progression through retinoblastoma protein hyperphosphorylation and through activation of both cyclin D1/cdk4 and cyclin E/cdk2 kinases by a mechanism that depends on induction of cyclin D1 and cyclin E protein levels. The induction of cyclin D1 expression, but not that of cyclin E, is under mitogen-activated protein kinase (MAPK) control, indicating an independent regulation of these two cyclins in the 5-HT2B receptor mitogenesis. Moreover, by using the specific platelet-derived growth factor receptor (PDGFR) inhibitor AG 1296 or by overexpressing a kinase-mutant PDGFR, we show that PDGFR kinase activity is essential for 5-HT2B-triggered MAPK/cyclin D1, but not cyclin E, signaling pathways. 5-HT2B receptor activation also increases activity of the Src family kinase, c-Src, Fyn, and c-Yes. Strikingly, c-Src, but not Fyn or c-Yes, is the crucial molecule between the G(q) protein-coupled 5-HT2B receptor and the cell-cycle regulators. Inhibition of c-Src activity by 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1) or depletion of c-Src is sufficient to abolish the 5-HT-induced (i) PDGFR tyrosine kinase phosphorylation and MAPK activation, (ii) cyclin D1 and cyclin E expression levels, and (iii) thymidine incorporation. This paper elucidates a model of 5-HT2B receptor mitogenesis in which c-Src acts alone to control cyclin E induction and in concert with the receptor tyrosine kinase PDGFR to induce cyclin D1 expression via the MAPK/ERK pathway.
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PMID:5-hydroxytryptamine 2B receptor regulates cell-cycle progression: cross-talk with tyrosine kinase pathways. 1068 5

The tyrosine kinase (TK) family includes many growth factor receptors, cell cycle regulators, and oncoproteins. Moreover, the receptor TKs HER2/neu and epidermal growth factor receptor are overexpressed in a subgroup of breast tumors and correlate with more aggressive behavior. Thus, TKs are being actively pursued as therapeutic targets. The purpose of this study was to determine the expression pattern of TKs in breast cancer. Reverse transcription-PCR was performed with degenerate primers based on conserved motifs of the catalytic domains of TKs, and the identities of the reverse transcription-PCR products were determined by digestion with a panel of restriction enzymes. Using a TK display assay, we studied the TK profiles of 13 breast cancer cell lines and two normal immortalized breast epithelial cell lines. The TK display assay reproducibly demonstrated known differences in HER-2/neu expression between cell lines. Several TKs, including receptor TKs Axl, Cak, fibroblast growth factor receptor 4, HEK8, HER2/neu, c-MET, RET, and nonreceptor TKs ARG, BRK, Janus kinase 1, Rak, and YES were detected in breast cancer cells. Several kinases were differentially expressed among the cell lines. Similar TK profiles were found using RNA from human breast tumors. We conclude that there is significant variability in the TK expression pattern of breast cancers. This variability should be considered when selecting TK inhibitors to treat patients.
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PMID:Expression profile of tyrosine kinases in breast cancer. 1183 50

The small G protein RAP1 and the kinase B-RAF have been proposed to link elevations of cAMP to activation of ERK/mitogen-activated protein (MAP) kinase. In order to delineate signaling pathways that link receptor-generated cAMP to the activation of MAP kinase, the human A(2A)-adenosine receptor, a prototypical G(s)-coupled receptor, was heterologously expressed in Chinese hamster ovary cells (referred as CHO-A(2A) cells). In CHO-A(2A) cells, the stimulation of the A(2A)-receptor resulted in an activation of RAP1 and formation of RAP1-B-RAF complexes. However, overexpression of a RAP1 GTPase-activating protein (RAP1GAP), which efficiently clamped cellular RAP1 in the inactive GDP-bound form, did not affect A(2A)-agonist-mediated MAP kinase stimulation. In contrast, the inhibitor of protein kinase A H89 efficiently suppressed A(2A)-agonist-mediated MAP kinase stimulation. Neither dynamin-dependent receptor internalization nor receptor-promoted shedding of matrix-bound growth factors accounted for A(2A)-receptor-dependent MAP kinase activation. PP1, an inhibitor of SRC family kinases, blunted both the A(2A)-receptor- and the forskolin-induced MAP kinase stimulation (IC(50) = 50 nm); this was also seen in PC12 cells, which express the A(2A)-receptor endogenously, and in NIH3T3 fibroblasts, in which cAMP causes MAP kinase stimulation. In the corresponding murine fibroblast cell line SYF, which lacks the ubiquitously expressed SRC family kinases SRC, YES, and FYN, forskolin barely stimulated MAP kinase; this reduction was reversed in cells in which c-SRC had been reintroduced. These findings show that activation of MAP kinase by cAMP requires a SRC family kinase that lies downstream of protein kinase A. A role for RAP1, as documented for the beta(2)-adrenergic receptor, is apparently contingent on receptor endocytosis.
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PMID:MAP kinase stimulation by cAMP does not require RAP1 but SRC family kinases. 1208 90

Primary cutaneous CD30+ anaplastic large cell lymphoma (C-ALCL) represents a distinct clinical subtype of CD30+ anaplastic large cell lymphomas. The etiology and underlying molecular pathogenesis of C-ALCL remain unclear. This study aimed to investigate genetic changes in C-ALCL. Comparative genomic hybridization (CGH) analysis of 23 DNA samples from 15 C-ALCL cases identified chromosome imbalances (CI) in 10 samples from eight cases (43%). The mean number of CI per sample was 2.09 +/- 3.86, with gains (2.00 +/- 3.85) more common than losses (0.09 +/- 0.29). The most frequent CI were gains of 1/1p and 5 (50%) and 6, 7, 8/8p, and 19 (38%). Microarray-based CGH analysis of six DNA samples from five cases with CI revealed genomic imbalances (GI) in all of the cases studied. This included oncogene copy number gains of FGFR1 (8p11) in three cases, and NRAS (1p13.2), MYCN (2p24.1), RAF1 (3p25), CTSB (8p22), FES (15q26.1), and CBFA2 (21q22.3) in two cases. Real-time PCR analysis of nine DNA samples from eight cases with CI and GI detected amplifications of CTSB and RAF1 in seven cases (88%), REL (2p13p12) and JUNB (19p13.2) in six cases (75%), and MYCN and YES1 (18p11.3) in four cases (50%). Immunohistochemical staining of paraffin sections from six cases demonstrated expression of JUNB protein in five cases and BCL2 in three cases. These results reveal a consistent pattern of genetic alterations in C-ALCL and provide the molecular basis for further investigation of this disease.
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PMID:Genetic alterations in primary cutaneous CD30+ anaplastic large cell lymphoma. 1269 66


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