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)

Hirschsprung disease (HSCR, aganglionic megacolon) is a common congenital malformation leading to bowel obstruction, with an incidence of 1/5,000 live births. It is characterized by the absence of intrinsic ganglion cells in the myenteric and submucosal plexuses along variable lengths of the gastrointestinal tract. As enteric neurons are derived from the vagal neural crest, HSCR is regarded as a neurocristopathy. On the basis of a skewed sex-ratio (M/F = 4/1) and a risk to relatives much higher than the incidence in the general population, HSCR has long been regarded as a sex-modified multifactorial disorder. Accordingly, segregation analysis suggested an incompletely penetrant dominant inheritance in HSCR families with aganglionosis extending beyond the sigmoid colon. We and others have mapped a dominant gene for HSCR to chromosome 10q11.2 and have ascribed the disease to mutations in the RET proto-oncogene. However, the lack of genotype-phenotype correlation, the low penetrance and the sex-dependent effect of RET mutations supported the existence of one or more modifier gene(s) in familial HSCR. In addition, thus far, RET mutations only accounted for 50% and 15-20% of familial and sporadic HSCR patients, respectively. RET encodes a tyrosine kinase receptor whose ligand was unknown. Recently, the Glial cell line-derived neurotrophic factor (GDNF) has been identified to be a ligand for RET. Moreover, Gdnf-/- knockout mutant mice display congenital intestinal aganglionosis and renal agenesis, a phenotype very similar to the Ret-/- mouse. These data prompted us to hypothesize that mutations of the gene encoding GDNF could either cause or modulate the HSCR phenotype in some cases.
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PMID:Germline mutations of the RET ligand GDNF are not sufficient to cause Hirschsprung disease. 889 69

The RET proto-oncogene is at the origin of one of the most interesting models of human disease caused by mutations in a receptor tyrosine kinase gene. Somatic rearrangements of RET are involved in the aetiology of a variable proportion of papillary thyroid carcinomas (PTC), the most common type of thyroid tumour whose prevalence is increasing in areas heavily exposed to radioactive fallout after the Chernobyl accident of 1986. Moreover, germline RET mutations are associated with the three variants of the inherited cancer syndrome known as multiple endocrine neoplasia type 2 (MEN2A, MEN2B and FMTC). Finally, RET mutations or heterozygous deletions of the whole gene cause the autosomal dominant form of Hirschsprung disease (HSCR), a congenital disorder of the enteric nervous system (ENS).
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PMID:RET mutations in human disease. 890 18

In order to evaluate the roles of the RET proto-oncogene in normal human tissues and tumors derived from the neural crest cells, we examined the expression of RET in a variety of adult human tissues, pheochromocytomas, medullary thyroid carcinomas (MTCs), ganglioneuromas, and a neurinoma. Northern blot analysis demonstrated that RET is normally expressed in the adrenal medulla and cerebellum among adult human tissues. RET transcripts were detected in all of 11 sporadic and one familial pheochromocytomas. The levels of RET mRNA were higher in 8 of 12 pheochromocytomas than in the normal adrenal medulla, indicating that RET is overexpressed in the majority of sporadic pheochromocytomas. There was a considerable difference in the level of RET expression in each pheochromocytoma ranging from 0.2 to 10 times the transcripts found in the normal adrenal medulla. The sizes of the transcripts of 7.0, 6.0, 4.5, and 3.9 kb were the same as those found in the adrenal medulla, suggesting no rearrangements of the RET gene in pheochromocytomas. Southern blot analysis revealed neither amplification nor gross structural changes in the RET gene. RET was also expressed at high levels in four MTCs examined, whereas its transcripts were detected at low abundance in only one of three ganglioneuromas. RET was not expressed in a neurinoma. These results suggest that RET may play some roles in a limited range of adult human tissues, and that its high levels of expression may have relevance to development or growth of pheochromocytomas and MTCs.
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PMID:Expression of the RET proto-oncogene in normal human tissues, pheochromocytomas, and other tumors of neural crest origin. 891 82

Germ line point mutations in the RET proto-oncogene have been implicated in four inherited disorders: multiple endocrine neoplasia 2A (MEN 2A) and 2B (MEN 2B); familial medullary thyroid carcinoma (FMTC); and Hirschprung's disease, a congenital lack of enteric plexus neurons. Oncogenically activated RET has also been demonstrated in some sporadic medullary thyroid tumors, which show somatic missense mutations in the same regions as those found in MEN 2B. Upon screening archival sporadic MTC tumor tissue by nonradioactive single-strand conformational polymorphism analysis (SSCP), a markedly divergent exon 11 pattern was found in an unusually aggressive neoplasm. Sequencing of PCR amplified DNA revealed the deletion of nine bases encompassing a key cysteine codon at position 1831-3, often altered in MEN 2A. Normal thyroid tissue from the same patient showed a normal SSCP pattern and sequence for this exon. This novel somatic mutation further implicates the RET proto-oncogene in the development of MTC.
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PMID:A novel deletion in the RET proto-oncogene found in sporadic medullary thyroid carcinoma. 891 60

The recent identification of mutations in the RET proto-oncogene that are associated with multiple endocrine neoplasia type 2 (MEN 2) syndromes has allowed therapeutic intervention in affected individuals on the basis of direct genetic testing. The principal endocrine neoplasm that occurs in patients with the MEN 2 syndromes is medullary thyroid carcinoma. This thyroid neoplasm is the only consistently malignant feature of the MEN 2 syndromes and it is the most common cause of death in affected patients. Kindred members at risk for one of the MEN 2 syndromes can be studied by direct DNA analysis to determine whether they have inherited a RET mutation. Those with a positive test can be treated by early thyroidectomy and cured when the disease is microscopic and localized to the thyroid gland. Total thyroidectomy is performed as early as 5 years of age and is associated with minimal morbidity and virtually no mortality. Residual or persistent medullary thyroid carcinoma following thyroidectomy can best be determined by detecting increased levels of calcitonin following the administration of intravenous calcium gluconate and pentagastrin.
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PMID:Genetic testing and early thyroidectomy for inherited medullary thyroid carcinoma. 894 70

We investigated the possible role of the RET proto-oncogene, which has recently been identified as the susceptibility gene for multiple endocrine neoplasia type 2, in the development of sporadic neuroendocrine tumors from different locations. DNA extracted from paraffin-embedded specimens of 112 neuroendocrine tumors was screened for somatic RET point mutations in exons 10, 11, 13, 15, and 16, where recently oncogenic mutations have been described in a subset of sporadic medullary thyroid carcinomas and pheochromocytomas. Methods employed included nonisotopic PCR-based single strand conformation polymorphism (PCR-SSCP) analysis, heteroduplex gel electrophoresis, and restriction enzyme digestion. The nucleotide sequence of samples with aberrant band patterns was identified by nonisotopic direct sequencing of PCR-amplified DNA. Forty-four percent (7/16) of sporadic medullary thyroid carcinomas and 15% (3/20) of pheochromocytomas contained a somatic, heterozygous point mutation at codon 918 of exon 16 (ATG --> ACG) causing a Met --> Thr substitution. None of the remaining 4 parathyroid adenomas, 8 pituitary adenomas, 17 pancreatic neuroendocrine tumors, 11 pulmonary and 10 gastrointestinal carcinoids, 7 small cell lung carcinomas, 5 neuroblastomas, 10 malignant melanomas, or 4 schwannomas contained mutations in any of the five RET exons tested. Although the numbers of each investigated neuroendocrine tumor type are small, our data indicate that oncogenic RET proto-oncogene mutations are involved in the formation of a subset of sporadically occurring medullary thyroid carcinomas and pheochromocytomas but do not appear to be generally important in the formation of other types of sporadically occurring neuroendocrine tumors.
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PMID:RET proto-oncogene point mutations in sporadic neuroendocrine tumors. 896 26

Missense germline mutations of the RET proto-oncogene have recently been identified in the hereditary cancer syndromes MEN2A, MEN2B, and FMTC, all characterized by medullary carcinoma, but also including phaeochromocytoma in MEN2A and MEN2B and parathyroid disease in MEN2A. In addition, somatic RET proto-oncogene mutations have been identified in a subset of sporadic medullary carcinomas and phaeochromocytomas. This study investigated the possibility that RET plays a role in sporadic parathyroid neoplasia. Firstly, normal and neoplastic parathyroid tissues were screened for expression of the RET proto-oncogene, using an RT-PCR approach on autopsy material. Secondly, 20 archival parathyroid adenomas were screened for somatic mutations in the transmembrane region of RET, the region associated with germline mutations in MEN2A and hence parathyroid disease, using a PCR-solid phase direct sequencing approach. RET expression was identified in all the parathyroid tissues analysed. However, no mutations were identified in any of the 20 adenomas, suggesting either that other mechanisms of RET activation occur, such as translocation, or that RET plays a more minor role in the growth control of the parathyroid cells than in C cells or phaeochromocytes.
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PMID:Analysis of the RET proto-oncogene in sporadic parathyroid adenomas. 897 70

Phaeochromocytomas usually occur sporadically but may also be a feature of three autosomal dominantly inherited cancer syndromes, multiple endocrine neoplasia type 2, von Hippel-Lindau disease (VHL), and, very rarely, type 1 neurofibromatosis. Germ-line missense mutations in the RET proto-oncogene, which encodes a receptor tyrosine kinase, cause multiple endocrine neoplasia type 2. In VHL, germ-line mutations in one of the three exons of the VHL tumor suppressor gene have been found in the majority of families. Whereas somatic mutations in the VHL gene have been common in sporadic renal cell carcinoma, a component cancer of VHL, somatic mutations in the RET and VHL genes together have been found in approximately 10% of sporadic phaeochromocytomas. Hence, other genes must also contribute to the pathogenesis of sporadic phaeochromocytomas. Recent data have suggested that glial cell line-derived neurotrophic factor (GDNF) is a ligand for RET and acts via a heterotetrameric receptor complex that includes GDNF receptor alpha, which provides ligand binding capabilities, and RET, which provides the signaling component. Thus, both GDNF and GDNFR-alpha are plausible candidate genes for involvement in the pathogenesis of phaeochromocytomas. To investigate the role of GDNF in sporadic phaeochromocytomas, we scanned a panel of 22 tumors. Among these samples, only a conservative sequence variant was detected in exon 2 of GDNF. No disease-associated somatic GDNF mutations or gross gene amplification were detected in these tumors, suggesting only a minor role for GDNF in the genesis of phaeochromocytomas.
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PMID:Mutation analysis of glial cell line-derived neurotrophic factor (GDNF), a ligand for the RET/GDNF receptor alpha complex, in sporadic phaeochromocytomas. 900 May 74

Germline mutations of the RET proto-oncogene, which codes for a receptor tyrosine kinase, cause multiple endocrine neoplasia type 2A (MEN 2A) and 2B (MEN 2B) and familial medullary thyroid carcinoma (FMTC). MEN 2 mutations have been shown to result in RET oncogenic activation. The RET gene encodes several isoforms whose biological properties, when altered by MEN 2 mutations, have not been thoroughly addressed yet. In this study, we have introduced a MEN 2A mutation (Cys634-->Arg) and the unique MEN 2B mutation (Met918-->Thr) in two RET isoforms of 1114 and 1072 amino acids which differ in the carboxy-terminus part. Herein, we report that each RET isoform activated by MEN 2A or MEN 2B mutation was transforming in fibroblasts and induced neuronal differentiation of pheochromocytoma PC12 cells. However, among the different RET-MEN 2 mutants, the long RET isoform activated by the MEN 2B mutation stimulated the most prominent neurite outgrowth in PC12 cells, while the short RET isoform counterpart elicited a very weak differentiation effect in PC12 cells. We further demonstrate that the morphological changes of PC12 cells caused by constitutively activated RET oncoproteins involved the engagement of a Ras-dependent pathway. These findings provide evidence that the biological properties of RET-MEN 2 mutants depend on the interplay between the RET isoforms and the nature of the activating MEN 2 mutation.
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PMID:Distinct biological properties of two RET isoforms activated by MEN 2A and MEN 2B mutations. 901 12

The RET proto-oncogene encodes two isoforms of a receptor type tyrosine kinase which plays a role in neural crest and kidney development. Distinct germ-line mutations of RET have been associated with the inherited cancer syndromes MEN2A, MEN2B and FMTC as well as with the congenital disorder Hirschsprung disease (HSCR), whereas somatic rearrangements (RET/PTCs) have been frequently detected in the papillary thyroid carcinoma. Despite these findings, suggesting a relevant role for RET product in development and neoplastic processes, little is known about the signalling triggered by this receptor. In this study, we have demonstrated that the transducing adaptor molecule Shc is recruited and activated by both Ret isoforms and by the rearranged cytoplasmatic Ret/ptc2 oncoproteins as well as by the membrane bound receptor activated by MEN2A or by MEN2B associated mutations. Moreover, our analysis has identified the Ret tyrosine residue and the Shc domains involved in the interaction. In fact, here we show that both the phosphotyrosine binding domains of Shc, PTB and SH2, interact with Ret/ptc2 in vitro. However, PTB domain binds 20 folds higher amount of Ret/ptc2 than SH2. The putative binding site for either SH2 and PTB domains has been identified as Tyr586 of Ret/ptc2 (Tyr1062 on proto-Ret). In keeping with this finding, by using RET/PTC2-Y586F mutant, we have demonstrated that this tyrosine residue, the last amino acid but one before the divergence of the two Ret isoforms, is the docking site for Shc.
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PMID:Identification of Shc docking site on Ret tyrosine kinase. 904 84


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