Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

KIT (CD117) is a 145-KD transmembrane glycoprotein that is the product of the kit-gene. As a member of the subclass III family of receptor tyrosine kinases, KIT is closely related to the receptors for platelet derived growth factor alpha and beta (PDGF-A and B), macrophage colony stimulating factor (M-CSF), and FLT3 ligand. The ligand for KIT, stem cell factor (SCF), also known as steel factor or mast cell growth factor promotes the dimerisation and autophosphorylation of KIT receptors. The phosphorylated tyrosine residues provide binding sites for signal molecules that contain SH2 domains. KIT mediated signal transduction is critical for the normal development and survival of haematopoietic progenitor cells, mast cells, interstitial cells of Cajal (intestinal pacemaker cells), melanocytes and germ cells. Upon differentiation, KIT expression is lost with the exception of mast cells, melanocytes and interstitial cells of Cajal. The detection of CD117 expression is of paramount diagnostic relevance in gastrointestinal stromal tumors (GIST). About 95% of all GISTs are immunohistochemically CD117 positive. The vast majority of all other sarcoma, carcinoma and also lymphoma are CD117 negative. Therefore, CD117 expression has a high sensitivity and specificity for the diagnosis of GIST. Moreover, activating mutations of KIT tyrosine kinase play a crucial pathogenetic role in GIST 80 to 85% of all GIST's contain activating mutations, primarily in Exon's 11 and 9 of the kit gene. Since the resulting mutant isoformes are sensitive to inhibition by imatinib (glivec), a specific tyrosine kinase inhibitor, the detection of a specific mutation has also a high predictive value. Besides GIST mastocytoses and seminomas are the neoplasias that most commonly express CD117. In contrast to GIST however, these two neoplasias contain mutations in different exons and are only partly imatinib sensitive. Moreover, CD117 expression is by no means entirely specific for these entities. It can also be detected in adenoid cystic carcinomas, thymic carcinomas and melanomas. Very rarely (< 5%) it can also be observed in other carcinomas and sarcomas. However, in the great majority of these cases with a CD117 protein expression there is no corresponding gene mutation of kit. Importantly, the lack of an activating mutation of KIT tyrosine kinase is good evidence that imatinib will not be effective. In other words, detection of sole CD117 protein expression is no solid basis for targeted therapy. The molecular pathological detection of CD117 expression in combination with the corresponding mutational status in patients with GIST (and other tumors) paradigmatically highlights the importance of modern molecular diagnostics in the era of targeted therapy.
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PMID:[The diagnostic and predictive role of kit (CD117)]. 1668 59

CEACAM1 (also known as CD66a) is a transmembrane glycoprotein that mediates homophilic intercellular interactions that influence cellular growth, immune cell activation, and tissue morphogenesis. Various studies have suggested a link between CEACAM1 and cellular apoptosis, including a recent demonstration that ERK1/2 signaling is triggered downstream of CEACAM1. In this study, we reveal that CEACAM1-long binding confers survival signals to human peripheral blood mononuclear cells. CEACAM-specific antibodies effectively protected peripheral blood mononuclear cells from apoptosis, with this effect being particularly dramatic for primary monocytes that undergo spontaneous apoptosis during in vitro culture. This protective effect was reiterated when using soluble CEACAM1, which binds to cell-surface CEACAM1 via homophilic interactions. Monocyte survival correlated with a CEACAM1-dependent up-regulation of the cellular inhibitor of apoptosis Bcl-2 and the abrogation of caspase-3 activation. CEACAM1 binding triggered a phosphatidylinositol 3-kinase-dependent activation of the protein kinase Akt without influencing the activity of extracellular signal-related kinase ERK, whereas the phosphatidylinositol 3-kinase-specific inhibitor LY294002 effectively blocked the protective effect of CEACAM1. Together, this work indicates that CEACAM1 confers a phosphatidylinositol 3-kinase- and Akt-dependent survival signal that inhibits mitochondrion-dependent apoptosis of monocytes. By controlling both ERK/MEK and PI3K/Akt pathways, CEACAM1 functions as a key regulator of contact-dependent control of cell survival, differentiation, and growth.
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PMID:CEACAM1 (CD66a) promotes human monocyte survival via a phosphatidylinositol 3-kinase- and AKT-dependent pathway. 1707 10

The Pop1/Bves (blood vessel/epicardial substance) gene is a member of the popeye gene family recently identified in various species. It encodes a potential transmembrane glycoprotein and is a cell adhesion molecule present in skeletal and cardiac muscle and epithelia. We isolated the Drosophila homologue of Bves (DmBves) and found, using in situ hybridisation to RNA in ovaries, that bves is expressed in all follicular epithelial cells surrounding the oocyte at stage 10, except those in very posterior and anterior-dorsal regions adjacent to the oocyte. We show that the repression of bves expression in anterior-dorsal follicle cells is regulated by the Grk/EGFR signalling pathway. Bves is also expressed in nurse cells during oogenesis and its transcripts are then translocated into the oocyte. Expression of bves antisense RNA during oogenesis causes reduced viability in the resulting embryos. There is a failure in the migration of pole cells from the posterior towards the antero-dorsal side of the embryo, probably resulting from abnormal germband extension and we suggest that bves is essential for normal embryonic development.
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PMID:Blood vessel/epicardial substance (bves) expression, essential for embryonic development, is down regulated by Grk/EFGR signalling. 1718 63

The MUC4 mucin is a transmembrane glycoprotein that is implicated in the pathogenesis of pancreatic cancer and is aberrantly expressed in many other epithelial carcinomas. Recent studies suggest its significant potential as a clinical tool for cancer diagnosis and prognosis. MUC4 modulates HER2/ErbB2 signaling and is a determinant of therapeutic outcome of Herceptin-based therapy, which further indicates its prospective usefulness in cancer therapy and treatment planning.
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PMID:Emerging roles of MUC4 in cancer: a novel target for diagnosis and therapy. 1723 48

MUC4, a high-molecular weight transmembrane glycoprotein, is overexpressed in pancreatic cancer and is implicated in its pathogenesis. It is a heterodimeric protein containing a large extracellular, heavily glycosylated subunit, MUC4alpha, and a transmembrane growth factor-like subunit, MUC4beta. In the present study, we have shown the interaction of human MUC4 with the receptor tyrosine kinase HER2 in pancreatic adenocarcinoma cells by reciprocal coimmunoprecipitation and cocapping studies. MUC4 colocalized with HER2 at the cell surface and in the cytoplasm. Silencing of MUC4 by transient or stable expression of MUC4-targeted short-interfering RNA led to the down-regulation of HER2 with a concomitant decrease in its phosphorylated form (pY(1248)-HER2). Further analyses revealed that the MUC4-knockdown-mediated decrease in HER2 expression occurred due to the drop in the stability of the receptor. In MUC4-knockdown pancreatic cancer cells, we also observed a reduced phosphorylation of the focal adhesion kinase and p42/44 mitogen-activated protein kinase, which are downstream effector proteins in HER2 signaling. Our findings add a new dimension to MUC4 function as a modulator of cell signaling and provide mechanistic evidence for its role in pancreatic cancer progression.
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PMID:MUC4 mucin interacts with and stabilizes the HER2 oncoprotein in human pancreatic cancer cells. 1838 9

The transmembrane glycoprotein signal regulatory protein/SHP2-substrate (SIRP1alpha/SHPS-1) has been implicated in growth factor- and cell adhesion-induced signalling. Here we report on the contribution of SIRP1alpha to IL-6 type cytokine signalling. SIRP1alpha binds the protein tyrosine phosphatase SHP2 upon treatment with interleukin-6 in a stimulation-dependent manner. Mouse embryonic fibroblasts expressing a SIRP1alpha protein which lacks the intracellular part show enhanced SHP2 phosphorylation and ERK1/2 activation in response to IL-6, suggesting that SIRP1alpha affects IL-6-signalling through SHP2. Whereas SHP2 phosphorylation is enhanced in SIRP1alpha-deficient cells STAT3 activation is delayed and STAT3-dependent gene induction is reduced which correlates with reduced STAT3 serine phosphorylation. Our results indicate that SIRP1alpha contributes to IL-6 signalling by counteracting SHP2 phosphorylation which consequently affects ERK-activation and STAT3-dependent transactivation as well as target gene expression. Our observations will help to understand the tight balance of MAPK- and STAT3-activation in response to IL-6 which was found to be misbalanced in many autoimmune diseases, inflammatory proliferative diseases and cancer.
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PMID:SHPS-1/SIRP1alpha contributes to interleukin-6 signalling. 1845 Apr 21

The mucin MUC4 is a high molecular weight transmembrane glycoprotein. It consists of a mucin-type subunit (MUC4alpha) and a transmembrane growth factor-like subunit (MUC4beta). The mucin MUC4 is overexpressed in many epithelial malignancies including ovarian cancer, suggesting a possible role in the pathogenesis of these cancers. In this study, we investigated the functional role of MUC4 in the human ovarian cancer cell line SKOV3. The mucin MUC4 was ectopically expressed by stable transfection, and its expression was examined by western blot and confocal microscopy analyses. The in vitro studies demonstrated an enhanced motility of MUC4-expressing SKOV3 cells compared with the vector-transfected cells. The mucin MUC4 expression was associated with apparent changes in actin organisation, leading to the formation of microspike, lammelopodia and filopodia-like cellular projections. An enhanced protein expression and activation of HER2, a receptor tyrosine kinase, was also seen, although no significant change was observed in HER-2 transcript levels in the MUC4-transfected SKOV3 cells. Reciprocal co-immunoprecipitation revealed an interaction of MUC4 with HER2. Further, the MUC4-overexpressing SKOV3 cells exhibited an increase in the phosphorylation of focal adhesion kinase (FAK), Akt and ERK, downstream effectors of HER2. Taken together, our findings demonstrate that MUC4 plays a role in ovarian cancer cell motility, in part, by altering actin arrangement and potentiating HER2 downstream signalling in these cells.
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PMID:MUC4 activates HER2 signalling and enhances the motility of human ovarian cancer cells. 1866 93

MUC1, a transmembrane glycoprotein, is abnormally over-expressed in most human adenocarcinomas. MUC1 association with cytoplasmic cell signal regulators and nuclear accumulation are important for its tumor related activities. Little is known about how MUC1 translocates from the cell membrane to the cytoplasm. In this study, live cell imaging was used to study MUC1 intracellular trafficking. The interaction between EGFR and MUC1 was mapped by FRET analysis and EGF stimulated MUC1 endocytosis was observed directly through live cell imaging. MUC1-CT endocytosis was clathrin and dynamin dependent. Rab5 over-expression resulted in decreased cell membrane localization of MUC1, with accumulation of MUC1 endocytic vesicles in the peri-nuclear region. Conversely, over-expression of a Rab5 dominant negative mutant (S34N) resulted in redistribution of MUC1 from the peri-nuclear region to the cytoplasm. Collectively, these results indicated that MUC1 intra-cellular trafficking occurs through a regulated process that was stimulated by direct EGFR and MUC1 interaction, mediated by clathrin coated pits that were dynamin dependent and regulated by Rab5.
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PMID:MUC1 intra-cellular trafficking is clathrin, dynamin, and rab5 dependent. 1881 66

CEACAM1 (carcinoembryonic antigen-related cell adhesion molecule 1), a type I transmembrane glycoprotein involved in cell-cell adhesion has been shown to act as an angiogenic factor for mouse and human endothelial cells. Based on the ability of CEACAM1 to initiate lumen formation in human mammary epithelial cells grown in 3D culture (Matrigel), we hypothesized that murine CEACAM1 may play a similar role in vasculogenesis. In order to test this hypothesis, murine embryonic stem (ES) cells stimulated with VEGF were differentiated into embryoid bodies (EB) for 8 days (-8-0 d) and transferred to Matrigel in the presence or absence of anti-CEACAM1 antibody for an additional 12 days (0-12 d). In the absence of anti-CEACAM1 antibody or in the presence of an isotype control antibody, the EB in Matrigel underwent extensive sprouting, generating lengthy vascular structures with well-defined lumina as demonstrated by confocal microscopy, electron microscopy, and immunohistochemical analysis. Both the length and architecture of the vascular tubes were inhibited by anti-CEACAM1 mAb CC1, a mAb that blocks the cell-cell adhesion functions of CEACAM1, thus demonstrating a critical role for this cell-cell adhesion molecule in generating and maintaining vasculogenesis. QRT-PCR analysis of the VEGF treated ES cells grown under conditions that convert them to EB revealed expression of Ceacam1 as early as -5 to -3 d reaching a maximum at day 0 at which time EBs were transferred to Matrigel, thereafter levels at first declined and then increased over time. Other markers of vasculogenesis including Pecam1, VE-Cad, and Tie-1 were not detected until day 0 when EBs were transferred to Matrigel followed by a steady increase in levels, indicating later roles in vasculogenesis. In contrast, Tie-2 and Flk-1 (VEGFR2) were detected on day five of EB formation reaching a maximum at day 0 on transfer to Matrigel, similar to Ceacam1, but after which Tie-2 declined over time, while Flk-1 increased over time. QRT-PCR analysis of the anti-CEACAM1 treated ES cells revealed a significant decrease in the expression of Ceacam1, Pecam1, Tie-1, and Flk-1, while VE-Cad and Tie-2 expression were unaffected. These results suggest that the expression and signaling of CEACAM1 may affect the expression of other factors known to play critical roles in vasculogenesis. Furthermore this 3D model of vasculogenesis in an environment of extracellular matrix may be a useful model for comparison to existing models of angiogenesis.
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PMID:Role of Ceacam1 in VEGF induced vasculogenesis of murine embryonic stem cell-derived embryoid bodies in 3D culture. 1928 68

CD133 (prominin-1) is a transmembrane glycoprotein expressed on the surface of normal and cancer stem cells (tumor-initiating cells), progenitor cells, rod photoreceptor cells and a variety of epithelial cells. Although CD133 is widely used as a marker of various somatic and putative cancer stem cells, its contribution to the fundamental properties of cancer cells, such as tumorigenesis and differentiation, remains to be elucidated. In the present report, we found that CD133 was expressed in several neuroblastoma (NB) cell lines/tumor samples. Intriguingly, CD133 repressed NB cell differentiation, for example neurite extension and the expression of differentiation marker proteins, and was decreased by several differentiation stimuli, but accelerated cell proliferation, anchorage-independent colony formation and in vivo tumor formation of NB cells. NB cell line and primary tumor-sphere experiments indicated that the molecular mechanism of CD133-related differentiation suppression in NB was in part dependent on neurotrophic receptor RET tyrosine kinase regulation. RET transcription was suppressed by CD133 in NB cells and glial cell line-derived neurotrophic factor treatment failed to induce RET in CD133-expressing cells; RET overexpression rescued CD133-related inhibition of neurite elongation. Of note, CD133-related NB cell differentiation and RET repression were mainly dependent on p38MAPK and PI3K/Akt pathways. Furthermore, CD133 has a function in growth and RET expression in NB cell line- and primary tumor cell-derived tumor spheres. To the best of our knowledge, this is the first report of the function of CD133 in cancer cells and our findings may be applied to improve differentiation induction therapy for NB patients.
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PMID:CD133 suppresses neuroblastoma cell differentiation via signal pathway modification. 2081 39


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