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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)
An expression cloning method which allows direct isolation of cDNAs encoding substrates for tyrosine kinases was applied to the study of the
epidermal growth factor (EGF) receptor
(
EGFR
) signaling pathway. A previously undescribed cDNA was isolated and designated eps15. The structural features of the predicted eps15 gene product allow its subdivision into three domains. Domain I contains signatures of a regulatory domain, including a candidate tyrosine phosphorylation site and EF-hand-type calcium-binding domains. Domain II presents the characteristic heptad repeats of coiled-coil rod-like proteins, and domain III displays a repeated aspartic acid-proline-phenylalanine motif similar to a consensus sequence of several methylases. Antibodies specific for the eps15 gene product recognize two proteins: a major species of 142 kDa and a minor component of 155 kDa, both of which are phosphorylated on tyrosine following
EGFR
activation by EGF in vivo.
EGFR
is also able to directly phosphorylate the eps15 product in vitro. In addition, phosphorylation of the eps15 gene product in vivo is relatively receptor specific, since the
erbB-2
kinase phosphorylates it very inefficiently. Finally, overexpression of eps15 is sufficient to transform NIH 3T3 cells, thus suggesting that the eps15 gene product is involved in the regulation of mitogenic signals.
...
PMID:eps15, a novel tyrosine kinase substrate, exhibits transforming activity. 768 53
We recently reported the molecular cloning of
HER4
/p180erbB4, a new member of the epidermal growth factor receptor family, as well as its activation by a partially purified ligand (Plowman, G. D., Culouscou, J.-M., Whitney, G. S., Green, J. M., Carlton, G. W., Foy, L., Neubauer, M. G., and Shoyab, M. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 1746-1750). In this report we describe the purification to homogeneity of a 45-kDa protein (p45) that induces the differentiation of MDA-MB-453 human breast cancer cells and stimulates the tyrosine phosphorylation of p180erbB4, the
HER4
-encoded protein. Hydrophobic interaction, ion-exchange, heparin, and size exclusion chromatographies were used to purify this p180erbB4 activator to homogeneity. N-terminal amino acid sequencing suggests that p45 is related to heregulin, a recently reported ligand for
p185erbB2
. Binding and cross-linking experiments demonstrated that p45 specifically binds to cells expressing recombinant p180erbB4 and not cells expressing recombinant
p185erbB2
.
...
PMID:Characterization of a breast cancer cell differentiation factor that specifically activates the HER4/p180erbB4 receptor. 768 52
The
HER4
/erbB-4 gene has been isolated as the fourth member of the human
EGFR
subfamily of tyrosine kinases and has been reported to encode a receptor for NDF/heregulin. In the present study we determined the chromosomal location of the
HER4
/erbB-4 gene within the human genome. Using human cDNA probes in fluorescence in situ hybridization (FISH), we mapped the
HER4
/erbB-4 gene to human chromosome 2q33.3-34. This finding established that also the
HER4
/erbB-4 gene is located in close vicinity of homeobox and collagen gene loci, as is the case for the related
EGFR
,
erbB-2
/neu and erbB-3. Aberrations of this chromosomal region associated with T cell leukemias and lymphomas as well as alveolar rhabdomyosarcomas raise the possibility that
HER4
/erbB-4 might be activated in these tumour types.
...
PMID:Localization of the human HER4/erbB-4 gene to chromosome 2. 770 Jun 49
SH2 domains function to bind proteins containing phosphotyrosine and are components of proteins that are important signal transducers for tyrosine kinases. We have cloned SH2 domain proteins by screening bacterial expression libraries with the tyrosine phosphorylated carboxyterminus of the
epidermal growth factor (EGF) receptor
. Here we report the identification of a new SH2 domain protein, Grb10. Grb10 is highly related to Grb7, an SH2 domain protein that we have previously identified. In addition to an SH2 domain, Grb7 and Grb10 have a central domain with similarity to a putative C. elegans gene likely to be involved in neuronal migration. At least three forms of Grb10 exist in fibroblasts apparently due to alternate translational start sites. Grb10 undergoes serine but not tyrosine phosphorylation after EGF treatment resulting in a shift mobility in a large fraction of Grb10 molecules. However Grb10 appears to bind poorly to EGF-Receptor and the true binding partner for the Grb10 SH2 domain is unclear. Grb10 maps to mouse chromosome 11 very close to the EGF-Receptor which is remarkably similar to Grb7 that maps near the EGF-Receptor related
HER2
receptor. The finding of multiple family members with evolutionarily conserved domains indicates that these SH2 domain proteins are likely to have an important, although as of yet, unidentified function.
...
PMID:The cloning of Grb10 reveals a new family of SH2 domain proteins. 773 17
The objective of the present study was to determine the frequency of amplifications of three different members of the erbB gene family in human glioblastoma multiforme (GBM). We investigated 47 glial tumors (37 GBM WHO grade IV, 5 anaplastic astrocytomas WHO III and 5 astrocytomas WHO II) by Southern and Western analysis, and immunocytochemistry. Gene amplification of erbB genes in human malignant gliomas was restricted to the EGF receptor (EGFR) gene, erbB-1. We found amplification of the EGFR gene in 49% (18/37) of GBM but not in the astrocytomas WHO II/III. The
erbB-2
and erbB-3 genes showed no amplification in the tumor specimens investigated in this study. At the protein level we found overexpression of the EGF receptor in 86% (32/37) by Western analysis and in 92% (34/37) by immunocytochemistry. Expression of the
ERBB2
protein was present in 54% (20/37) but immunoreactivity was much weaker than for EGF receptor and in most cases barely detectable by Western analysis and immunocytochemistry. The ERBB3 protein was not expressed in the glial tumors investigated in this study. Of the three erbB genes only gene amplification and overexpression of the EGF receptor seems to have an impact on tumor progression of human gliomas. Our data from immunohistochemistry indicate that
ERBB2
expression in GBM is closely correlated with EGF receptor levels and is therefore not useful as an independent prognostic parameter.
...
PMID:Amplification and differential expression of members of the erbB-gene family in human glioblastoma. 776 96
The proto-oncogene
HER2
/neu encodes for a 185 kDa transmembrane protein with extensive homology to the
epidermal growth factor (EGF) receptor
. We have previously shown a correlation between
HER2
/neu expression and the level of in vitro cytotoxicity of tumour-associated lymphocytes (TAL) versus autologous tumour. In addition, we have recently demonstrated that tumour-associated cytotoxic T-lymphocytes (CTL) from ovarian and breast cancer patients can recognize a
HER2
/neu derived peptide epitope when presented in the context of HLA-A2. Since repeated tumour stimulation of CTL enhances both proliferation and cytotoxicity against autologous tumour, we hypothesized that repeated peptide antigen stimulation would have a similar effect. To be therapeutically useful, the peptide antigen must meet the following conditions: (1) the peptide must be immunogenic and cause a proliferation of CTL to adequate therapeutic numbers, and (2) the peptide-specific CTL which are generated must be cytotoxic against autologous tumour. To test our hypothesis, T-lymphocytes isolated from the ascites of four consecutive
HER2
/neu+ ovarian cancer patients were initially stimulated with solid phase anti-CD3 antibody and divided into three groups: (1) treatment with recombinant interleukin-2 (IL-2) alone, (2) IL-2 plus weekly stimulation with irradiated autologous tumour cells, and (3) IL-2 plus weekly stimulation with a
HER2
/neu derived peptide. Peptide-stimulated and tumour-stimulated CTL showed similar increases in proliferation with both groups consistently reaching therapeutic numbers. Peptide-stimulated CTL demonstrated significantly enhanced cytotoxicity against autologous tumour in 4-h chromium release assays as compared to the IL-2 alone group.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:In vitro stimulation of ovarian tumour-associated lymphocytes with a peptide derived from HER2/neu induces cytotoxicity against autologous tumour. 778 Jun 12
Shc is a ubiquitously expressed Src homology 2 (SH2) domain protein that can transform fibroblasts and differentiate PC12 cells in a Ras-dependent fashion. Shc binds a variety of tyrosine-phosphorylated growth factor receptors presumably via its carboxyl-terminal SH2 domain. We cloned a fragment of Shc when screening a bacterial expression library with tyrosine-phosphorylated
epidermal growth factor (EGF) receptor
. Surprisingly, this fragment encodes the amino terminus of Shc, a region that has no significant similarity to an SH2 domain. When expressed as a glutathione S-transferase fusion protein, this amino-terminal domain binds to autophosphorylated EGF receptor, as well as
HER2
/neu and TrkA receptors. This fragment acts like an SH2 domain in that it does not bind non-phosphorylated EGF receptor or EGF receptor with all tyrosine phosphorylation sites mutated or deleted. Our data define a novel domain in Shc that has the potential to interact with growth factor receptors and other tyrosine-phosphorylated proteins.
...
PMID:A region in Shc distinct from the SH2 domain can bind tyrosine-phosphorylated growth factor receptors. 779 94
Insulin-stimulated glucose transport in adipocytes is mediated by the insulin receptor. To ascertain whether a related receptor could also trigger this response, the
epidermal growth factor (EGF) receptor
(
EGFR
) was introduced into adipocytes. 3T3-L1 fibroblasts were infected by a retroviral construct encoding either the full-length (WT) or a carboxy-terminal truncated (c'973) human
EGFR
; truncation of the amino acids distal to 973 removes all autophosphorylation motifs. After selection and conversion to adipocytes, the level of
EGFR
expression was retained in infectant adipocytes (150,000 and 250,000/cell, respectively), but not in the parental 3T3-L1 adipocytes (< 5000/cell). WT and c'973
EGFR
exhibited ligand-dependent tyrosine kinase activity and stimulated mitogen-activated protein kinase activity equivalently; neither phosphorylated insulin receptor substrate-1. WT
EGFR
, but not c'973
EGFR
, underwent ligand-induced autophosphorylation. EGF did not stimulate tyrosine phosphorylation of the insulin receptor or insulin receptor substrate-1. EGF had a minimal effect on glucose transport by parental 3T3-L1 adipocytes. Glucose transport in the WT
EGFR
adipocytes was stimulated equivalently by insulin and EGF; exposure to insulin and EGF in combination did not result in augmented transport. Glucose transport in the c'973
EGFR
adipocytes was stimulated by insulin, but not by EGF. GLUT4 was translocated to the plasma membrane to a similar extent in response to insulin or EGF in the WT
EGFR
adipocytes; only insulin caused a significant GLUT4 translocation in the parental or c'973
EGFR
adipocytes. These data suggest that the insulin and EGF signaling pathways that lead to glucose transport converge in these adipocytes down-stream of the insulin receptor, and that activation of this pathway requires signaling motifs in the carboxy-terminus of the
EGFR
. This model system represents a novel approach with which to dissect signal transduction pathways in terminally differentiated adipocytes.
...
PMID:Epidermal growth factor (EGF) receptor carboxy-terminal domains are required for EGF-induced glucose transport in transgenic 3T3-L1 adipocytes. 783 73
Overexpression of the c-
erbB-2
/
HER2
protooncogene in breast carcinoma is controlled not only by the degree of amplification of the gene but also at the level of gene transcription. Thus, whether or not the gene is amplified, the activity of the c-
erbB-2
promoter is enhanced in overexpressing cells through the binding of an additional transcription factor, OB2-1, whose activity is increased in these lines. Here we describe further characterization of OB2-1 and show that it is identical to the developmentally regulated transcription factor AP-2. Functional assays confirm that AP-2 is able to regulate c-
erbB-2
expression in mammary-derived cell lines. Furthermore, although AP-2 is barely detectable in cells with the low c-
erbB-2
expression phenotype, protein levels are clearly elevated in a panel of c-
erbB-2
-overexpressing lines. These findings demonstrate an important role for this transcription factor in human cancer.
...
PMID:The developmentally regulated transcription factor AP-2 is involved in c-erbB-2 overexpression in human mammary carcinoma. 784 46
The
HER4
/
ERBB4
gene encodes a 180K transmembrane protein (
HER4
/p180erbB4) that is structurally related to the 185K product (
HER2
/
p185erbB2
) of the
HER2
/
ERBB2
proto-oncogene. A 45K heparin-binding glycoprotein (p45) has been characterized that specifically activates the intrinsic tyrosine kinase activity of
HER4
(ref. 2). This
HER4
ligand shares several features with the heregulin family of proteins, including molecular mass, ability to induce differentiation of breast cancer cells, activation of tyrosine phosphorylation in MDA-MB453 cells, and amino-terminal protein sequence. Heregulin exists as multiple isoforms and all are presumed to interact directly with
HER2
(refs 3-6). We have used binding and phosphorylation studies with recombinant ligand on cell lines expressing recombinant receptors, and report here that heregulin, like p45, is a specific ligand for
HER4
. Furthermore, heregulin fails to induce phosphorylation of
HER2
in the absence of
HER4
. These findings suggest that activation of the
HER4
receptor is involved in signal transduction by heregulin.
...
PMID:Heregulin induces tyrosine phosphorylation of HER4/p180erbB4. 790 37
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