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)

Oncogenic rearrangements of the NTRK1 gene (also designated TRKA), encoding one of the receptors for the nerve growth factor, are frequently detected in thyroid carcinomas. Such rearrangements fuse the NTRK1 tyrosine kinase domain to 5'-end sequences belonging to different genes. In previously reported studies we have demonstrated that NTRK1 oncogenic activation involves two genes, TPM3 and TPR, both localized similarly to the receptor tyrosine kinase, on the q arm of chromosome 1. Here we report the characterization of a novel NTRK1-derived thyroid oncogene, named TRK-T3. A cDNA clone, capable of transforming activity, was isolated from a transformant cell line. Sequence analysis revealed that TRK-T3 contains 1,412 nucleotides of NTRK1 preceded by 598 nucleotides belonging to a novel gene that we have named TFG (TRK-fused gene). The TRK-T3 amino acid sequence displays, within the TFG region, a coiled-coil motif that could endow the oncoprotein with the capability to form complexes. The TRK-T3 oncogene encodes a 68-kDa cytoplasmic protein reacting with NTRK1-specific antibodies. By sedimentation gradient experiments the TRK-T3 oncoprotein was shown to form, in vivo, multimeric complexes, most likely trimers or tetramers. The TFG gene is ubiquitously expressed and is located on chromosome 3. The breakpoint producing the TRK-T3 oncogene occurs within exons of both the TFG gene and the NTRK1 gene and produces a chimeric exon that undergoes alternative splicing. Molecular analysis of the NTRK1 rearranged fragments indicated that the chromosomal rearrangement is reciprocal and balanced and involves loss of a few nucleotides of germ line sequences.
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PMID:The DNA rearrangement that generates the TRK-T3 oncogene involves a novel gene on chromosome 3 whose product has a potential coiled-coil domain. 756 64

Neuroblastomas demonstrate both clinical and biological heterogeneity. We have proposed that neuroblastomas may be classified in three genetically distinct subtypes, based on cytogenetic and molecular analysis. The first comprises those with hyperdiploid or triploid modal karyotypes (or compatible DNA content by flow cytometry), 1p LOH and MYCN amplification are absent, and TRKA expression is high. These patients are likely to be infants with low stages of disease (stages 1, 2, or 4S by the International Neuroblastoma Staging System), and they have a very favourable outcome (> 90% cure). The second group consists of tumours that generally have a near diploid or tetraploid modal chromosome number or DNA content but lack MYCN amplification. They usually have 1p allelic loss, 14q allelic loss or other structural changes, and TRKA expression is usually low. These patients are generally older with advanced stages of disease (stages 3 or 4), and they have a slowly progressive course, with a cure rate of 25-50%. The third group is characterised by tumours with MYCN amplification. These tumours are generally near diploid or tetraploid, with 1p allelic loss, and low or absent TRKA expression. The patients are usually between 1 and 5 years of age with advanced stages of disease, and they have a very poor prognosis (< 5%). It remains to be determined if tumours in one group ever evolve into a less unfavourable group, but current evidence suggests that they are distinct genetically. The identification of the oncogenes, suppressor genes and growth factor receptor pathways involved in neuroblastomas has provided great insight into the mechanisms of malignant transformation and progression, and ultimately they may provide the targets for future therapy.
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PMID:Molecular basis for heterogeneity in human neuroblastomas. 757 54

Tumors are believed to arise as a result of an accumulation of mutations in critical genes involved in the control of cell proliferation. Thyroid neoplasms represent a good model for studying the role of these mutations in epithelial cell multistep carcinogenesis because they comprise a broad spectrum of lesions with different degrees of malignancy. Recent reports have described the involvement of specific genetic alterations in different types of thyroid neoplasms. Papillary carcinomas are characterized by the activation of the receptor tyrosine kinases RET and TRK-A proto-oncogenes. Ras point mutations are frequently observed in tumors with follicular histology and a high prevalence of p53 point mutations have been found in anaplastic carcinomas. A definition of molecular defects characterizing thyroid tumors will be helpful in establishing sensitive and specific detection strategies and, in addition, to define genetic and environmental factors important for their pathogenesis.
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PMID:Molecular defects in thyroid carcinomas: role of the RET oncogene in thyroid neoplastic transformation. 758 78

There is increasing evidence that neutrophins and their receptors play an important role in regulating development of both the central and the peripheral nervous systems. Human TRK-A (NTRK1) and TRK-C (NTRK3) have been cloned and sequenced, but only a truncated form of human TRK-B has been published. Therefore, we isolated complementary DNAs spanning the entire coding region of both human full-length and truncated forms of TRK-B from human brain cDNA libraries. Human full-length TRK-B codes for a protein of 822 amino acid residues. The putative mature peptide sequence is 49% homologous to human TRK-A and 55% to full-length human TRK-C, with 40% amino acid identify among TRK-A, -B, and -C. Nine of 13 cysteine residues, 4 of 12N-glycosylation sites in the extracellular domain, and 10 of 13 tyrosine residues in the intracellular domain are conserved among human TRK-A, -B, and -C. There is a cluster of 10 serine residues in the juxtamembrane region of TRK-B that is absent in TRK-A. Two major sizes of TRK-B transcripts were expressed in human brain. Northern blot analysis using probes specific for the extracellular or the tyrosine kinase domain revealed that the 9.5-kb band encodes the full-length TRK-B mRNA and the 8.0-kb band encodes the truncated form of TRK-B mRNA. By fluorescence in situ hybridization and somatic cell hybrid mapping, the human TRK-B gene was localized to chromosome 9q22.1.
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PMID:Cloning and chromosomal localization of the human TRK-B tyrosine kinase receptor gene (NTRK2). 778 88

Protein tyrosine kinases have been implicated in tumor initiation and progression. Here we used Northern blotting to study expression of their genes in cultured normal melanocytes and 19 melanoma cell lines from different stages of tumor progression. We detected transcripts for 2 cytoplasmic (ABL and FES) and 6 receptor (ECK, ERB-B2, FGF-R4, IGFI-R, KDR and TIE) kinases but not for receptors RET or TRK-A. Genes for ECK, FGF-R4 and TIE were expressed ectopically in melanomas (not in normal melanocytes). Similarly, ECK protein was detected by immunoblotting in metastatic melanomas but not in normal melanocytes. ECK mRNA levels tended to increase again during late melanoma progression. ECK and TIE mRNAs were also detected in highly metastatic variant cells but not in the corresponding poorly metastatic parental lines. Conversely, FES and KDR gene expression was lost in most advanced primary and metastatic melanomas. These findings suggest positive and negative roles for specific tyrosine kinases during progression.
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PMID:Abnormal protein tyrosine kinase gene expression during melanoma progression and metastasis. 781 45

There is considerable interest in the role of the TRK family of neuotrophin receptors in regulating growth and differentiation in normal and neoplastic nerve cells. A neuroblastoma is a common pediatric tumor derived from the neural crest, and the majority of favorable neuroblastomas express a high level of TRK-A mRNA. However, little is known about the expression or function of TRK-B in these tumors. TRK-B encodes a tyrosine kinase that binds to brain-derived neuotrophic factor (BDNF), as well as neurotrophin-3 (NT-3) and NT-4/5. We have studied the N-myc-amplified human neuroblastoma cell line, SMS-KCN, which expresses both TRK-B and BDNF. Exogenous BDNF induces tyrosine phosphorylation of TRK-B as well as phosphorylation of phospholipase C-gamma 1, the extracellular signal-regulated kinases 1 and 2, and phosphatidylinositol-3 kinase. BDNF also induces expression of the immediate-early genes c-FOS and NGFI-A but not NGFI-B or NGFI-C. In addition, BDNF appears to promote cell survival and neurite outgrowth. SMS-KCN cells also express TRK-A, which is phosphorylated in response to nerve growth factor. However, the downstream TRK-A signaling is apparently defective. Finally, we determined that in a series of 74 primary neuroblastomas, 36% express TRK-B mRNA, 68% express BDNF mRNA, and 31% express both. Truncated TRK-B appears to be preferentially expressed in more-differentiated tumors (ganglioneuromas and ganglioneuroblastomas), whereas full-length TRK-B is expressed almost exclusively in immature neuroblastomas with N-myc amplification. Our findings suggest that in TRK-B-expressing human neuroblastomas, BDNF promotes survival and induces neurite outgrowth in an autocrine or paracrine manner. The BDNF/TRK-B pathway may be particularly important for growth and differentiation of neuroblastomas with N-myc amplification.
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PMID:Expression and function of TRK-B and BDNF in human neuroblastomas. 826 43

Congenital insensitivity to pain with anhidrosis (CIPA; MIM 256800) is an autosomal-recessive disorder characterized by recurrent episodes of unexplained fever, anhidrosis (absence of sweating) and absence of reaction to noxious stimuli, self-mutilating behaviour and mental retardation. The genetic basis for CIPA is unknown. Nerve growth factor (NGF) induces neurite outgrowth and promotes survival of embryonic sensory and sympathetic neurons. Mice lacking the gene for TrkA, a receptor tyrosine kinase for NGF, share dramatic phenotypic features of CIPA, including loss of responses to painful stimuli, although anhidrosis is not apparent in these animals. We therefore considered the human TRKA homologue as a candidate for the CIPA gene. The mRNA and genomic DNA encoding TRKA were analysed in three unrelated CIPA patients who had consanguineous parents. We detected a deletion-, splice- and missense-mutation in the tyrosine kinase domain in these three patients. Our findings strongly suggest that defects in TRKA cause CIPA and that the NGF-TRKA system has a crucial role in the development and function of the nociceptive reception as well as establishment of thermoregulation via sweating in humans. These results also implicate genes encoding other TRK and neurotrophin family members as candidates for developmental defect(s) of the nervous system.
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PMID:Mutations in the TRKA/NGF receptor gene in patients with congenital insensitivity to pain with anhidrosis. 869 25

Hereditary sensory neuropathy Type II (HSN II) is an autosomal recessive disorder characterized by the loss of peripheral sensory modalities in individuals with otherwise normal development. Patients with HSN II often have chronic ulceration of the fingers and toes, autoamputation of the distal phalanges, and neuropathic joint degeneration associated with loss of pain sensation. Recent descriptions of a similar phenotype in mice carrying a targeted mutation in the low affinity nerve growth factor receptor, p75NGFR, suggested the possibility that mutations in this gene or other members of the nerve growth factor (NGF) family of genes and their receptors might be responsible for this human disorder. In this study candidate genes were evaluated by their inheritance pattern in two sisters affected with HSN II, their unaffected sister and mother in a consanguineous family. The segregation of polymorphic alleles at and around loci for p75NGFR, TRKA, TRKB, BDNF, and familial dysautonomia (another hereditary sensory neuropathy having features in common with HSN II) virtually excluded these genes as the cause of HSN II in this family. Further evaluation of loci for other neurotrophic factors and their receptors, which will be possible when mapping information on their loci becomes available, may permit the identification of the gene responsible for HSN II.
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PMID:Exclusion of p75NGFR and other candidate genes in a family with hereditary sensory neuropathy type II. 927 17

The mitogen-activated protein kinase (MAPK) cascade plays a crucial role in the transduction of extracellular signals into responses governing growth and differentiation. The effects of a specific inhibitor of the MAPK kinase (MEK)/MAPK pathway (PD98059) on nerve growth factor (NGF)-induced growth arrest and inhibition of cell cycle-dependent kinases (CDKs) have been examined. Treatment of NIH 3T3 cells expressing TRKA with PD98059 dramatically reversed the complete inhibition of growth of these cells caused by NGF. PD98059 also blocked the ability of NGF to inhibit the activities of CDK4 and CDK2, while partially preventing NGF induction of p21Cip1/WAF1. To independently evaluate the involvement of the MEK/MAPK pathway in growth arrest, an inducible activated form of the Raf-1 protooncogene (delta RAF-1:ER) was expressed in these cells. Activation of delta RAF-1:ER resulted in a prolonged increase in MAPK activity and growth arrest of these cells, with concomitant induction of p21Cip1/WAF1 and inhibition of CDK2 activity. These effects of delta RAF-1:ER activation were all reversed by treatment of cells with PD98059. These data indicate that in addition to functioning as a positive effector of growth, stimulation of the MEK/MAPK pathway can result in an inhibition of CDK activity and cell cycle arrest.
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PMID:Cell cycle arrest mediated by the MEK/mitogen-activated protein kinase pathway. 901 3

TRKA expression was evaluated on 122 untreated neuroblastomas by immunohistochemistry using an antibody with predetermined specificity. This procedure is simple and reliable for protein detection at cellular level in a routine clinical setting. Fourteen tumours were classified as benign ganglioneuroma with a restricted expression of TRKA on ganglion cells; these patients were excluded from the following analysis. A total of 108 tumours were classified as neuroblastoma or ganglioneuroblastoma; 74 expressed TRKA protein, which strongly correlated with low stage, absence of N-MYC amplification, age (<1 year), CD44 expression and favourable clinical outcome. In a univariate analysis including tumour stage, age, histology, N-MYC amplification, CD44 and TRKA expression, all parameters had significant prognostic value. The absence of TRKA expression on CD44-positive or N-MYC non-amplified tumours permits the characterization of a subgroup of patients with intermediate prognosis. However, in a multivariate analysis taking into consideration the prognostic factors mentioned above, CD44 and tumour stage were the only independent prognostic factors for the prediction of patients' event-free survival.
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PMID:Clinical relevance of TRKA expression on neuroblastoma: comparison with N-MYC amplification and CD44 expression. 909 63


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