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)

Thrombin stimulates synthesis and secretion of endothelin-1 (ET-1), a vasoactive peptide that triggers responses in the vascular endothelium and smooth muscle. We investigated the signal transduction pathways by which thrombin stimulates preproET-1 gene expression and ET-1 peptide secretion in macrovascular cells (human umbilical vein endothelial cells [HUVECs] and bovine pulmonary artery endothelial cells [BPAECs]) and microvascular cells (human microvascular endothelial cell line [HMEC-1]). Thrombin (4 U/mL) stimulated maximal induction of ET-1 peptide secretion and preproET-1 mRNA after 2 hours in HUVECs and BPAECs and after 1 hour in HMEC-1. A synthetic thrombin receptor activator peptide confirmed ligand-specific receptor actions to induce preproET-1 mRNA. Protein kinase C (PKC) activation by phorbol ester transiently induced preproET-1 mRNA but had no effect on ET-1 peptide synthesis. PKC inhibitors sangivamycin and calphostin C and PKC depletion failed to suppress thrombin-stimulated preproET-1 mRNA. Adenylate cyclase and cAMP-dependent protein kinase did not participate in thrombin-induced preproET-1 gene activation. Thrombin stimulated a rapid increase in phosphotyrosine-containing proteins, suggesting a role for tyrosine phosphorylation in thrombin signaling. These data demonstrate that thrombin induces the preproET-1 gene and ET-1 peptide synthesis by a PKC-independent PTK-dependent pathway in macrovascular and microvascular endothelial cells. Protein tyrosine kinase inhibitors herbimycin A and genistein blocked thrombin-stimulated preproET-1 mRNA and peptide secretion, whereas daidzein, which lacks inhibitory activity, did not suppress thrombin-induced ET-1.
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PMID:Thrombin induces the preproendothelin-1 gene in endothelial cells by a protein tyrosine kinase-linked mechanism. 775 70

Protein tyrosine kinase transmembrane receptors trigger signal transduction cascades upon ligand binding, resulting in cellular proliferation, differentiation, differentiation inhibition or apoptosis depending upon the cell target. The ETK2/TYRO3 receptor is a tyrosine kinase expressed in embryonic stem cells, brain and testis that has recently been cloned by several groups. Analysis of cDNA clones isolated from several tissues shows 2 isoforms of the Etk2/tyro3 gene product that result from usage of alternative exons near the 5' end of the gene. In addition, our data suggest that a third alternative exon is positioned between these two alternative exons. This novel exon encodes yet another isoform that predicts a unique amino-terminal protein sequence. The alternative exons (exons 2A, 2B and 2C), predict three isoforms with different initiation codons, signal sequences and lengths. The existence of these multiple isoforms may be important for protein processing, translocation, or function.
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PMID:Identification of alternative exons, including a novel exon, in the tyrosine kinase receptor gene Etk2/tyro3 that explain differences in 5' cDNA sequences. 778 69

Protein tyrosine kinases (PTKs) have been implicated in the development of many common human tumours including melanoma. Previously we isolated PTK gene sequences expressed in normal melanocytes. Here we examined expression of 9 of these genes in cell lines derived from defined stages of melanoma progression, by Northern blotting and in some cases immunoblotting. We also tested cells from 2 animal models of particular stages in progression, as well as uncultured biopsies of metastatic melanoma. The expression of 2 receptor kinase family members found in melanocytes, PTK7/CCK-4 and SEK/TYRO1, was decreased or lost in advanced melanomas. PTK7 mRNA was found in only 54% of melanoma cell lines and 20% of melanoma biopsies. Similarly, expression was lost in 2 advanced cell lines selected from an early melanoma line that did express PTK7 mRNA. SEK/TYRO1 expression was observed in 75% and 17% of cell lines from primary and metastastic melanomas, respectively. Conversely, mRNA for the non-receptor kinase PTK6/BRK was not detected in normal melanocytes or primary melanoma lines, but was found in 9% of metastatic melanoma cell lines.
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PMID:Loss of expression of receptor tyrosine kinase family genes PTK7 and SEK in metastatic melanoma. 918 12

Psoriasis is a heterogenous skin disease, characterized by epidermal hyperproliferation, abnormal keratinization and inflammation. The heterogeneity of the disease results probably from the interaction of multiple gene abnormalities with environmental factors. The new approaches to drug design have become refocused to the emerging understanding of the role of signaling pathways in health and disease. Protein tyrosine kinases (PTKs) regulate cell proliferation, differentiation and immune processes. Uncontrolled signaling from receptor and intracellular tyrosine kinases can lead to numerous proliferative diseases: cancer, leukemia, restenosis and psoriasis. Identification of PTKs that play a key role in a defined disease can lead to a selective drug. The balance of signals which regulate the homeostasis of normal epidermis is altered in psoriasis. Several lines of evidence suggest a role for the EGF receptor system in this process. Therefore, blockers of the EGFR kinase were suggested as potent antipsoriasis agents. PTK inhibitors from the tyrphostin family were found to block EGF - dependent cell proliferation. AG 1571 (SU 5271) potently inhibits ligand-induced autophosphorylation of EGF-R, downstream signal transduction events, DNA replication and cell cycle progression at micromolar concentrations, as well as proliferation of keratinocytes isolated from psoriatic lesions in excellent correlation with its EGFR kinase inhibitory activity in these cells. AG 1571 (SU 5271) has been in clinical trials by SUGEN Inc. since early 1997. Overexpression of the EGFR is the hallmark of most epithelial cancers. Therefore one can view blockers of the EGFR kinase as becoming universal inhibitors. Tyrphostins are the first signal transduction agents to be used in the clinic. This article summarizes recent progress in the development of PTK inhibitors in the treatment of psoriasis.
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PMID:Inhibitors of tyrosine kinases in the treatment of psoriasis. 1082 17

Protein tyrosine kinase and protein serine kinase activation has been implicated in the regulation of salivary cell proliferation and differentiation. Aberrant expression and alterations of certain tyrosine or serine kinases, such as Raf or erbB2, are known to trigger salivary tumor development (Li et al., 1997; Cho et al., 1999). It has been estimated that there are about 1000 to 2000 protein kinases in the mammalian genome, with 100 to 200 of them (i.e., 10%) being tyrosine kinase (Hanks and Hunter, 1995). At present, there are approximately 85 different tyrosine kinases identified in the GenBank database. Based on the relatively slow rate of discovery in the past few years, 100 is a better approximation of the total number of tyrosine kinases encoded by each mammalian genome. It is reasonable to assume that there are about 30 to 50 tyrosine kinases expressed in a given cell at a given differentiation/proliferation stage. This number is large enough to provide a characteristic tissue-specific tyrosine kinase expression profile, but small enough to be identified in a simple screening. The hope for tyrosine kinases as differentiation or proliferation markers rests with the possibility for the identification and characterization of a differentiation/proliferation stage-specific expression pattern in salivary cells. Several ligands that transmit signal through receptor tyrosine kinases and/or Ras/Raf/ERK kinases have been extensively studied in salivary cells. This review focuses mainly on the signaling pathways activated by Raf and Etk.
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PMID:Salivary cellular signaling and gene regulation. 1184 28

Protein tyrosine kinase-7 (PTK7) is a receptor protein tyrosine kinase (RPTK)-like molecule that contains a catalytically inactive tyrosine kinase domain. We report here the genomic structure of the human PTK7 gene by screening a BAC library and DNA sequencing. The PTK7 gene is organized into 20 exons. All of the splicing junctions followed the conserved GT/AG rule. The exon-intron structure of the PTK7 gene in the region that encodes the catalytic domain was distinct from those of other RPTKs with strong homology. The 5'-flanking sequence of the PTK7 gene contains two GC boxes that concatenate Sp1 binding motifs, but does not contain either the TATA or CAAT consensus sequence. Using a luciferase reporter assay, it was demonstrated that the 883-bp 5'-flanking sequence is functional as a promoter of the PTK7 gene. We identified four new splicing variants in testis that could be derived from alternative splicing of exons 8-10, 10, a part of 12-13, and 16. The expression patterns of the splicing variants in the hepatoma and colon cancer cells were different from those of the testis. Our findings suggest that PTK7 is evolutionarily distinct from other RPTKs, and that the alternative splicing of PTK7 mRNA may contribute to its diverse function in cell signaling.
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PMID:Organization of the human PTK7 gene encoding a receptor protein tyrosine kinase-like molecule and alternative splicing of its mRNA. 1242 50

Complex signaling pathways operate in human embryonic stem cells (hESCs) and are coordinated to maintain self-renewal and stem cell characteristics in them. Protein tyrosine kinases (PTKs) participate in diverse signaling pathways in various types of cells. Because of their functions as key molecules in various cellular processes, PTKs are anticipated to have important roles also in hESCs. In this study, we investigated the roles of PTKs in undifferentiated and differentiated hESCs. To establish comprehensive PTK expression profiles in hESCs, we performed reverse transcriptase PCR using degenerate primers according to the conserved catalytic PTK motifs in both undifferentiated and differentiated hESCs. Here, we identified 42 different kinases in two hESC lines, including 5 non-receptor tyrosine kinases (RTKs), 24 RTKs, and 13 dual and other kinases, and compared the protein kinase expression profiles of hESCs and retinoic acid-treated hESCs. Significantly, up- and downregulated kinases in undifferentiated hESCs were confirmed by real-time PCR and western blotting. MAP3K3, ERBB2, FGFR4, and EPHB2 were predominantly upregulated, while CSF1R, TYRO3, SRC, and GSK3A were consistently downregulated in two hESC lines. Western blot analysis showed that the transcriptional levels of these kinases were consistent with the translational levels. The obstruction of upregulated kinases' activities using specific inhibitors disturbed the undifferentiated status and induced the differentiation of hESCs. Our results support the dynamic expression of PTKs during hESC maintenance and suggest that specific PTKs that are consistently up- and downregulated play important roles in the maintenance of stemness and the direction of differentiation of hESCs.
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PMID:Expression profiles of protein tyrosine kinase genes in human embryonic stem cells. 1858 72

Over expression of receptor tyrosine kinases is responsible for the development of a wide variety of malignancies. Termination of growth factor signaling is primarily determined by the down regulation of active growth factor/receptor complexes. In recent years, considerable insight has been gained in the endocytosis and degradation of growth factor receptors. A crucial player in this process is the EGFR Protein tyrosine kinase Substrate #15, or Eps15. This protein functions as a scaffolding adaptor protein and is involved both in secretion and endocytosis. Eps15 has been shown to bind to AP-1 and AP-2 complexes, to bind to inositol lipids and to several other proteins involved in the regulation of intracellular trafficking. In addition, Eps15 has been detected in the nucleus of mammalian cells. Activation of growth factor receptors induces tyrosine phosphorylation and mono-ubiquitination of Eps15. The role of these post translational modifications of Eps15 is still a mystery. It is proposed that Eps15 and its family members Eps15R and Eps15b are involved in the regulation of membrane morphology, which is required for intracellular vesicle formation and trafficking.
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PMID:Eps15: a multifunctional adaptor protein regulating intracellular trafficking. 1981 98

The fourth edition of the World Health Organization (WHO) classification of myeloid neoplasms refined the criteria for some previously described myeloid neoplasms and recognized several new entities based on recent elucidation of molecular pathogenesis, identification of new diagnostic and prognostic markers, and progress in clinical management. Protein tyrosine kinase abnormalities, including translocations or mutations involving ABL1, JAK2, MPL, KIT, PDGFRA, PDGFRB, and FGFR1, have been used as the basis for classifying myeloproliferative neoplasms (MPN). Two new entities - refractory cytopenia with unilineage dysplasia and refractory cytopenia of childhood have been added to the group of myelodysplastic syndromes (MDS), and 'refractory anemia with excess blasts-1' has been redefined to emphasize the prognostic significance of increased blasts in the peripheral blood. A list of cytogenetic abnormalities has been introduced as presumptive evidence of MDS in cases with refractory cytopenia but without morphologic evidence of dysplasia. The subgroup 'acute myeloid leukemia (AML) with recurrent genetic abnormalities' has been expanded to include more molecular genetic aberrations. The entity 'AML with multilineage dysplasia' specified in the 2001 WHO classification has been renamed 'AML with myelodysplasia-related changes' to include not only cases with significant multilineage dysplasia but also patients with a history of MDS or myelodysplasia-related cytogenetic abnormalities. The term 'therapy-related myeloid neoplasms' is used to cover the spectrum of disorders previously known as t-AML, t-MDS, or t-MDS/MPN occurring as complications of cytotoxic chemotherapy and/or radiation therapy. In this review, we summarize many of these important changes and discuss some of the diagnostic challenges that remain.
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PMID:Recent advances in the diagnosis and classification of myeloid neoplasms--comments on the 2008 WHO classification. 2062 69

Protein tyrosine kinase 7 (PTK7) is a pseudokinase whose precise function in regulating angiogenesis remains unknown. The purpose of this study was to define the mechanisms by which PTK7 promotes vascular endothelial growth factor-A (VEGF-A)-induced angiogenesis in vivo and in vitro. Immunoblotting was used to measure PTK7 expression in several types of vascular endothelial cells. Using both immunoprecipitation and immunoblotting, PTK7 was found to join a receptor complex with Flt-1 (VEGFR1), but not with KDR/Flk-1 (VEGFR2) or with Flt-4 (VEGFR3). By surface plasmon resonance analysis, the interaction between Flt-1 and PTK7 was confirmed and found to be intensified by VEGF-A. Flt-1 phosphorylation and downstream signals of Akt, and focal adhesion kinase (FAK) thus induced were down-regulated by inhibition of PTK7 expression using siRNA. Moreover, PTK7 overexpression in endothelial cells resulted in enhanced angiogenesis in vitro. In contrast, neovascularization induced in vivo by VEGF-A pellets was significantly decreased by injection of siRNA targeting PTK7. These data suggest that PTK7 serves an essential role in Flt-1-mediated angiogenesis.
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PMID:Flt-1 regulates vascular endothelial cell migration via a protein tyrosine kinase-7-dependent pathway. 2146 Feb 47


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