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)

We have isolated a murine cDNA encoding a ligand for the Cek7 receptor protein-tyrosine kinase (RPTK), a member of the Eph/Eck RPTK subfamily. Sequence analysis predicts an open reading frame of 209 amino acids with a predicted molecular mass of 24 kDa. The Cek7 ligand shows a 48% sequence identity at the protein level to B61, a ligand for the related Eck RPTK, 30% to the Cek5 ligand, 59% to the recently cloned Ehk1-L, and identity to ELF-1, a recently described ligand for the Mek4 and Sek RPTKs. The expressed Cek7 ligand is functionally active as it induces autophosphorylation of the Cek7 RPTK.
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PMID:cDNA cloning and characterization of a Cek7 receptor protein-tyrosine kinase ligand that is identical to the ligand (ELF-1) for the Mek-4 and Sek receptor protein-tyrosine kinases. 787 76

The Eph family of receptors, the largest subgroup within the tyrosine protein kinase receptor family, are comprised of at least thirteen members, many of which are predominantly expressed in the developing and adult nervous system. In this study, we have isolated a full-length cDNA, encoding the mouse homologue of a previous partially characterized Eek protein, a member of Eph receptor tyrosine kinase family. In a comparison of the amino acid sequences of various Eph family members, Eek is most similar to Ehk-3/MDK1, Sek/Cek8, Ehk-2, Hek/Mek4/Cek4, and Bsk/Ehk1/Rek7/Cek7, which are predominantly expressed in the nervous system. Additionally, we have used a low-stringency PCR cloning technique to identify ligands, related to B61, that may interact with Eek. Three different GPI-linked ligands, namely Elf-1/Cek7-L, Ehk1-L/Efl-2/Lerk3 and AL-1/RAGS, were isolated from mouse brain. To study the functional interactions between these ligands and the Eek receptors, we have constructed chimeric ligands consisting of the Fc portion of human IgG fused to their carboxyl-terminus. These chimeric ligands bound to, and activated both the Eek receptors and the Eek-TrkB chimeric receptors expressed in NIH3T3 cells. These findings suggest that Eek receptor can be activated by at least three different GPI-linked ligands.
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PMID:The Eek receptor, a member of the Eph family of tyrosine protein kinases, can be activated by three different Eph family ligands. 905 51

Topographic projection is a general feature of brain architecture and is critical for appropriate information processing and coding. Nevertheless, little is known about the mechanisms that govern topographic organization. The Eph family receptor tyrosine kinases and ligands have recently been implicated in the specification of topographic maps. We have shown that Bsk, an Eph family receptor, and its ligands are expressed in a complementary fashion in neurons and targets, respectively, in several neural systems. For example, in the hippocampus, Bsk is expressed in an increasing lateral to medial gradient. In contrast, at least three different ligands, viz., Elf-1, LERK3/Ehk1-L, and AL-1/RAGS/LERK7, are transcribed in complementary (opposing) gradients in the hippocampal subcortical target, the lateral septum. However, the spatial and temporal distribution of the ligands are different, such that combinatorially they specify the full target region during development. Consistent with a key role in hippocamposeptal topographic projection, the ligands selectively inhibit the growth of the topographically inappropriate medial hippocampal neurites but sustain the growth of the appropriate lateral neurites. Our studies indicate that the interaction of Bsk and its ligands restricts the receptor-positive medial neurons to the topographically appropriate, ligand-poor dorsal septal target. In addition to the hippocamposeptal system, Bsk and its ligands are also expressed in afferents and targets of several other systems, including the olfactory and the retinotectal systems. Consequently, Bsk and its ligands may play important roles in neuron-target interactions in multiple neural circuits.
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PMID:Regulation of topographic projection by the Eph family receptor Bsk (EphA5) and its ligands. 932 86

EFNA1, EFNA2, EFNA3, EFNA4, EFNA5, EFNB1, EFNB2 and EFNB3 are EFN family ligands for EPH family receptors. EFN/EPH signaling pathway networks with the WNT signaling pathway during embryogenesis, tissue regeneration, and carcinogenesis. Comparative genomics analyses on EFNB1, EFNB2 and EFNB3 were performed by using bioinformatics and human intelligence (humint). EFNB1 mRNA was expressed in human embryonic stem (ES) cells, neural tissues, diffuse type gastric cancer, pancreatic cancer, colon cancer, brain tumors and esophageal cancer, EFNB2 mRNA in human ES cells, neural tissues and colon cancer, EFNB3 mRNA in human ES cells, neural tissues, brain tumors, pancreatic cancer and colon cancer. Because triple TCF/LEF-binding sites were identified within the 5'-promoter region of human EFNB3 gene, comparative genomics analyses on EFNB3 orthologs were further performed. Chimpanzee EFNB3 gene, consisting of five exons, was identified within AC164921.3 genome sequence. AY421228.1 was not a correct coding sequence for chimpanzee EFNB3. Chimpanzee EFNB3 gene was found to encode a 340-amino-acid protein showing 99.4% and 96.6% total-amino-acid identity with human EFNB3 and mouse Efnb3, respectively. Three TCF/LEF-binding sites within human EFNB3 promoter were conserved in chimpanzee EFNB3 promoter, and the second TCF/LEF-binding site in rodent Efnb3 promoters. CpG hypermethylation of EFNB3 promoter with 63.2% GC content as well as deletion of EFNB3 gene closely linked to TP53 tumor suppressor gene at human chromosome 17p13.1 should be investigated to elucidate the mechanism of infrequent EFNB3 upregulation in human colorectal cancer. EFNB3, identified as potential transcriptional target of WNT/beta-catenin signaling pathway, is a pharmacogenomics target in the fields of regenerative medicine and oncology.
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PMID:Comparative integromics on Ephrin family. 1659 16

A 2.5 years old girl presented with moderate mental retardation, microcephaly, arching eyebrows, low set ears, long eyelashes, persistent fetal pads and clinodactyly. About 1 Mb deletion in the chromosomal region 1q21.3 was identified using BAC array CGH analysis. The parental follow up FISH analysis was normal. Further study of the deletion using a 244K oligo-array of Agilent Technologies Inc., Santa Clara, CA, USA defined the deleted region to span about 1.4 Mb with approximate genomic location chr1:152,511,593-153,993,103 (NCBI genome build 36). This is a novel deletion, not reported to-date. Larger proximal 1q deletions that were previously reported typically included microcephaly, mental retardation and multiple congenital anomalies. The deleted region reported here includes at least 30 coding genes. Among them of interest is a three-gene cluster of the ephrin gene family (EFNA1, EFNA3 and EFNA4). This is a group of receptor protein-tyrosine kinase type genes with presumed, but not completely characterized function in nervous system development.
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PMID:A novel 1.4 Mb de novo microdeletion of chromosome 1q21.3 in a child with microcephaly, dysmorphic features and mental retardation. 1977 33

Ephrin B1 and its cognate receptor, Eph receptor B2, key regulators of embryogenesis, are expressed in human atherosclerotic plaque and inhibit adult human monocyte chemotaxis. Few data exist, however, regarding the gene expression profiles of the ephrin (EFN) and Eph receptor (EPH) family of genes in atherosclerosis-related human cells. Gene expression profiles were determined of all 21 members of this gene family in atherosclerosis-related cells by reverse transcription-polymerase chain reaction analysis. The following 17 members were detected in adult human peripheral blood monocytes: EFNA1 and EFNA3 - EFNA5 (coding for ephrins A1 and A3 - A5); EPHA1, EPHA2, EPHA4 - EPHA6 and EPHA8 (coding for Eph receptors A1, A2, A4 - A6 and A8); EFNB1 and EFNB2 (coding for ephrins B1 and B2); and EPHB1 - EPHB4 and EPHB6 (coding for Eph receptors B1 - B4 and B6). THP-1 monocytic cells, Jurkat T cells and adult arterial endothelial cells also expressed multiple EFN and EPH genes. These results indicate that a wide variety of ephrins and Eph receptors might affect monocyte chemotaxis, contributing to the development of atherosclerosis. Their pathological significance requires further study.
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PMID:Expression profiling of the ephrin (EFN) and Eph receptor (EPH) family of genes in atherosclerosis-related human cells. 2167 56

Colorectal cancer (CRC), one of the most prevalent cancers in the western world, is treatable if detected early. However, 70% of CRC is detected at an advanced stage. This is largely due to the inadequacy of current faecal occult blood screening testing and costs involved in conducting population-based colonoscopy, the 'gold standard' for CRC detection. Another biomarker for CRC, carcinoembryonic antigen, while useful for monitoring CRC recurrence, is ineffective, lacking the specificity required early detection of CRC. For these reasons there is a need for more effective blood-based markers for early CRC detection. In this study we targeted glycoproteins secreted from the human colon carcinoma cell line LIM1215 as a source of potential CRC biomarkers. Secreted candidate glycoproteins were confirmed by MS and validated by Western blot analysis of tissue/tumour interstitial fluid (Tif) from LIM1215 xenograft tumours grown in immunocompromised mice. Overall, 39 glycoproteins were identified in LIM1215 culture media (CCM) and 5 glycoproteins in LIM1215 tumour xenograft Tif; of these, cadherin-17 (CDH17), galectin-3 binding protein (LGALS3BP), and tyrosine-protein kinase-like 7 (PTK7) were identified in both CM and glycosylation motifs. Swiss-Prot was used to annotate Tif. Many of the glycoproteins identified in this study (e.g., AREG, DSG2, EFNA1, EFNA3, EFNA4, EPHB4, ST14, and TIMP1) have been reported to be implicated in CRC biology. Interestingly, the cadherin-17 ectodomain, but not full length cadherin-17, was identified in CM, Tif and plasma derived from mice bearing the LIM1215 xenograft tumour. To our knowledge, this is the first report of the cadherin-17 ectodomain in plasma. In this study, we report for the first time that the presence of full-length cadherin-17 in exosomes released into the CM. This article is part of a Special Issue entitled: An Updated Secretome.
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PMID:Detection of cadherin-17 in human colon cancer LIM1215 cell secretome and tumour xenograft-derived interstitial fluid and plasma. 2355 62

Eph receptors and ephrin ligands are master regulators of oncogenic signaling required for proliferation, migration, and metastasis. Yet, Eph/ephrin expression and activity in medulloblastoma (MB), the most common malignant brain tumor of childhood, remains poorly defined. We hypothesized that Eph/ephrins are differentially expressed by sonic hedgehog (SHH) and non-SHH MB and that specific members contribute to the aggressive phenotype. Affymetrix gene expression profiling of 29 childhood MB, separated into SHH (N = 11) and non-SHH (N = 18), was performed followed by protein validation of selected Eph/ephrins in another 60 MB and two MB cell lines (DAOY, D556). Functional assays were performed using MB cells overexpressing or deleted for selected ephrins. We found EPHB4 and EFNA4 almost exclusively expressed by SHH MB, whereas EPHA2, EPHA8, EFNA1 and EFNA3 are predominantly expressed by non-SHH MB. The remaining family members, except EFNB1, are ubiquitously expressed by over 70-90 % MB, irrespective of subgroup. EFNB1 is the only member differentially expressed by 28 % of SHH and non-SHH MB. Corresponding protein expression for EphB/ephrinB1 and B2 was validated in MB. Only ephrinB2 was also detected in fetal cerebellum, indicating that EphB/ephrinB1 expression is MB-specific. EphrinB1 immunopositivity localizes to tumor cells within MB with the highest proliferative index. EphrinB1 overexpression promotes EphB activation, alters F-actin distribution and morphology, decreases adhesion, and significantly promotes proliferation. Either silencing or overexpression of ephrinB1 impairs migration. These results indicate that EphrinB1 is uniquely dysregulated in MB and promotes oncogenic responses in MB cells, implicating ephrinB1 as a potential target.
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PMID:EphrinB1 expression is dysregulated and promotes oncogenic signaling in medulloblastoma. 2525 52