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)

Multiple endocrine neoplasia type 2B (MEN2B) is an autosomal dominant syndrome characterized by the development of medullary thyroid carcinoma, pheochromocytomas, musculoskeletal anomalies and mucosal ganglioneuromas. MEN2B is caused by a specific mutation (Met918-->Thr) in the RET receptor tyrosine kinase. Different mutations of RET lead to other conditions including MEN2A, familial medullary thyroid carcinoma and intestinal aganglionosis (Hirschsprung disease). Transgenic mice were created using the dopamine beta-hydroxylase promoter to direct expression of RET(MEN2B) in the developing sympathetic and enteric nervous systems and the adrenal medulla. DbetaH-RET(MEN2B) transgenic mice developed benign neuroglial tumors, histologically identical to human ganglioneuromas, in their sympathetic nervous systems and adrenal glands. The enteric nervous system was not affected. The neoplasms in DbetaH-RET(MEN2B) mice were similar to benign neuroglial tumors induced in transgenic mice by activated Ras expression under control of the same promoter. Levels of phosphorylated MAP kinase were not increased in the RET(MEN2B)-induced neurolglial proliferations, suggesting that alternative pathways may play a role in the pathogenesis of these lesions. Transgenic mice with the highest levels of DbetaH-RET(MEN2B) expression, unexpectedly developed renal malformations analogous to those reported with loss of function mutations in the Ret gene.
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PMID:Ganglioneuromas and renal anomalies are induced by activated RET(MEN2B) in transgenic mice. 1002 63

During kidney development, factors from the metanephric mesenchyme induce the growth and repeated branching of the ureteric bud, which gives rise to the collecting duct system and also induces nephrogenesis. One signaling pathway known to be required for this process includes the receptor tyrosine kinase RET and co-receptor GFR(&agr;)-1, which are expressed in the ureteric bud, and the secreted ligand GDNF produced in the mesenchyme. To examine the role of RET signaling in ureteric bud morphogenesis, we produced transgenic mice in which the pattern of RET expression was altered, or in which a ligand-independent form of RET kinase was expressed. The Hoxb7 promoter was used to express RET throughout the ureteric bud branches, in contrast to its normal expression only at the bud tips. This caused a variable inhibition of ureteric bud growth and branching reminiscent of, but less severe than, the RET knockout phenotype. Manipulation of the level of GDNF, in vitro or in vivo, suggested that this defect was due to insufficient rather than excessive RET signaling. We propose that RET receptors expressed ectopically on ureteric bud trunk cells sequester GDNF, reducing its availability to the normal target cells at the bud tips. When crossed to RET knockout mice, the Hoxb7/RET transgene, which encoded the RET9 isoform, supported normal kidney development in some RET-/- animals, indicating that the other major isoform, RET51, is not required in this organ. Expression of a Hoxb7/RET-PTC2 transgene, encoding a ligand-independent form of RET kinase, caused the development of abnormal nodules, outside the kidney or at its periphery, containing branched epithelial tubules apparently formed by deregulated growth of the ureteric bud. This suggests that RET signaling is not only necessary but is sufficient to induce ureteric bud growth, and that the orderly, centripetal growth of the bud tips is controlled by the spatially and temporally regulated expression of GDNF and RET.
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PMID:Dominant effects of RET receptor misexpression and ligand-independent RET signaling on ureteric bud development. 1006 31

Multiple endocrine neoplasia type 2 (MEN2) and Hirschsprung's disease (HSCR) are two dominantly inherited neurocristopathies ascribed to mutations in the RET gene [Chakravarti, 1996; Pasini et al., 1996; Eng and Mulligan, 1997]. MEN2 is a cancer syndrome comprising three related clinical subtypes: (1) MEN type 2A (MEN2A; MIM# 171400) characterized by the association of medullary thyroid carcinoma (MTC), pheochromocytoma (Pheo), and hyperparathyroidism; (2) MEN type 2B (MEN2B; MIM# 162300), which includes MTC, Pheo, mucosal neuromas, ganglioneuromatosis of the digestive tract, and skeletal abnormalities; and (3) familial MTC (FMTC; MIM# 155240), defined by the sole occurrence of MTC. HSCR (MIM# 142623) is a congenital malformation caused by the absence of enteric plexuses in the hindgut, leading to bowel obstruction in neonates. The RET gene (MIM# 164761) codes for a transmembrane tyrosine kinase, a component of a multimeric complex that also comprises one of four members of a novel family of glycosylphosphatidylinositol (GPI)-anchored receptor, GFRalpha((1-4) (e.g., GFRA1, MIM# 601496; references are detailed in Baloh et al. [1998]. Four structurally related soluble factors-glial cell line-derived neurotrophic factor (GDNF), neurturin, persephin, and artemin-are the ligands of these multimolecular receptors in which the nature of the GFRalpha determines the ligand specificity of the complex [see Baloh et al., 1998, for references]. It is well documented that RET/GFRalpha-1/GDNF delivers a signal critical for the survival of the early neural crest-derived precursors that colonize the intestine below the rostral foregut and give rise to the enteric nervous plexuses [Gershon, 1997; Cacalano et al., 1998; Enomoto et al., 1998].
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PMID:Co-segregation of MEN2 and Hirschsprung's disease: the same mutation of RET with both gain and loss-of-function? 1022 Jan 48

Familial hyperparathyroidism (FHPT) is a hereditary disease where hyperparathyroidism (HPT) is transmitted in an autosomal dominant fashion. FHPT consists of a variety of diseases such as multiple endocrine neoplasia type1 (MEN 1) and type2 (MEN 2), familial isolated hyperparathyroidism (FIHPT) with single adenoma and with multiple adenomas (or hyperplasia), and FHPT with jaw-tumor (FHPT-JT). Isolation of the genes responsible for MEN1, and 2, i.e. MEN1 and RET, respectively, makes it possible to examine the relations among disorders constituting FHPT. We studied germ-line mutations in these 2 genes in a family of FHPT with single parathyroid adenoma. The disorder in this family was proved to be an entity different from MEN1 because no germ-line mutations in MEN1 gene were found in the affected members. The loss of heterozygosity (LOH) at MEN1 gene and PYGM were not found in the abnormal parathyroid in this family, supporting the above conclusion. No mutations in exons 10, and 11 of RET proto-oncogene was found in germ-line DNA of the affected member of the family, suggesting no relation to MEN2A. Linkage study excluded the possibility of FHPT-JT syndrome. PRAD1 was not overexpressed in the parathyroid tumors in this family. The relation of this disorder to FIHPT with multiple enlarged parathyroid glands remains to be clarified. A search for the gene(s) predisposing to FIHPT is needed.
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PMID:Familial isolated hyperparathyroidism caused by single adenoma: a distinct entity different from multiple endocrine neoplasia. 1039 44

A 44-year-old woman complained of headache and palpitation. Magnetic resonance imaging showed bilateral adrenal tumors 10 x 9 cm in size on the left side and 8 x 4 cm in size on the right side. CT scan revealed a 0.7 x 0.7 cm mass in the thyroid. Hormonal examinations showed high values of urinary cathecholamines and serum calcitonin. DNA sequence analysis of peripheral white blood cells revealed that codon 634 in exon 11 of the RET gene was mutated from TGC (Cys) to TAC (Tyr). From these findings, a diagnosis was made of MEN2A with bilateral adrenal pheochromocytomas and medullary thyroid carcinoma. Bilateral adrenalectomy and thyroidectomy were performed. The same mutation of the RET gene was detected in all her 3 children, in two of whom, early stage medullary thyroid carcinoma was detected and thyroidectomy was performed. DNA analysis of the RET gene was useful for the diagnosis of carriers of MEN2A and the early detection of medullary thyroid carcinoma.
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PMID:[A case of multiple endocrine neoplasia type 2A (MEN2A) with a mutation in the RET gene]. 1044 82

Co-localization of the glial cell line-derived neurotrophic factor (GDNF) and its functional receptor c-RET was examined immunohistochemically in the dorsal root ganglion (DRG) of the 5th lumbar nerve in rats. The total 1728 DRG neurons were observed in three female rats (Wistar) with ca. 200 g body weight, 46.6% of small neurons, 41.4% of medium-sized neurons, and 8.4% of large neurons showed GDNF-immunoreactivity. C-RET immunoreactivity was more intense in small and medium-sized DRG neurons than in large ones; it was detected in 43.8% of small neurons, 52.0% of medium-sized neurons and 14.5% of large neurons. On examination of alternate serial sections, each of which was immunostained for GDNF and c-RET, 16.1% of small neurons, 16.9% of medium-sized neurons, and 2.4% of large neurons showed both GDNF- and c-RET-immunoreactivities. Ligation of the sciatic nerve caused an accumulation of GDNF immunoreactive products more prominently in the ganglion side rather than the peripheral side of ligation. Our present results suggested that GDNF was always expressed in DRG neurons and was transported to spinal dorsal horn via the primary afferent neurons.
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PMID:Co-localization of the glial cell-line derived neurotrophic factor and its functional receptor c-RET in a subpopulation of rat dorsal root ganglion neurons. 1055 81

The tyrosine kinase receptor Ret is expressed in the ureteric bud and is required for normal renal development. Constitutive loss of Ret, its co-receptor gfralpha-1, or the ligand glial cell line-derived neurotrophic factor results in renal agenesis. Transgenic embryos that express a constitutively active form of Ret (Ret(MEN2B)) under the control of the dopamine-beta-hydroxylase (DbetaH) promoter develop profound neuroglial hyperplasia of their sympathetic ganglia and adrenal medullae. Embryos from two independent DbetaH-Ret(MEN2B)-transgenic lines exhibit renal malformations. In contrast with ret-/- embryos, renal maldevelopment in DbetaH-Ret(MEN2B)-transgenic embryos results from primary changes in sympathoadrenal organs extrinsic to the kidney. The ureteric bud invades the metanephric mesenchyme normally, but subsequent bud branching and nephrogenesis are retarded, resulting in severe renal hypoplasia. Ablation of sympathoadrenal precursors restores normal renal growth in vivo and in vitro. We postulate that disruption of renal development results because Ret(MEN2B) derived from the hyperplastic nervous tissue competes with endogenous renal Ret for gfralpha-1 or other signaling components. This hypothesis is supported by the observation that renal malformations, which do not normally occur in a transgenic line with low levels of DbetaH-Ret(MEN2B) expression, arise in a gdnf+/- background. However, renal maldevelopment was not recapitulated in kidneys that were co-cultured with explanted transgenic ganglia in vitro. Our observations illustrate a novel pathogenic mechanism for renal dysgenesis that may explain how putative activating mutations of the RET gene can produce a phenotype usually associated with RET deficiency.
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PMID:Sympathoadrenal hyperplasia causes renal malformations in Ret(MEN2B)-transgenic mice. 1059 45

Pheochromocytomas are rare tumours, with an incidence of 1-2 per million which arise from chromaffin cells of the adrenal medulla. They occur sporadically or as part of dominantly inherited cancer syndromes like multiple endocrine neoplasia 2 (MEN2A and 2B) and others. Continuous cell lines, not available so far, are essential tools for studies in these tumours. A continuous cell line (KNA) was established from a sporadic pheochromocytoma of the right adrenal gland of a 73-year-old woman. The KNA cells grow as suspensions of spheroids and show the morphological and immunocytochemical characteristics of neuronal chromaffin cells, such as neuroendocrine granules, and positive reactions to chromogranin- and related peptide-, neuron specific enolase and vasoactive intestinal peptide antibodies. Neurite-like processes are formed after addition of nerve growth factor. Chromosomal analyses revealed a diploid (46,XX,n = 50) to hypodiploid (43-45,XX,n = 15) karyotype. In hypodiploid metaphases most frequently #19, #17, #21 and #22 were missing. Chromosome arms 1p and 4q showed apparently consistent interstitial deletions: 6q, 8q, 13q and 22q showed clonal interstitial deletions. The cell line shows a heterozygous sequence variant TGC (cysteine) to TGG (tryptophan) in codon 611 in exon 10 of the RET proto-oncogene. So far, PC-12, a rat adrenal pheochromocytoma, has been the only continuous pheochromocytoma cell line available. KNA represents the first report on a human continuous pheochromocytoma cell line, the first report of structural chromosome aberrations in pheochromocytomas and the first report of a RET mutation TGC to TGG in exon 10 of the RET proto-oncogene in a sporadic pheochromocytoma.
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PMID:First continuous human pheochromocytoma cell line: KNA. Biological, cytogenetic and molecular characterization of KNA cells. 1064 Jan 77

Human thyroid tumors can be derived either from epithelial follicular cells or from parafollicular C-cells. Follicular cell-derived tumors represent a wide spectrum of lesions, ranging from benign adenomas through differentiated (follicular and papillary) and undifferentiated (anaplastic) carcinomas, thus providing a good model for finding a correlation between specific genetic lesions and histologic phenotype. Follicular adenomas and carcinomas show frequently the presence of mutations in one of the three ras genes. Papillary carcinomas show frequently a specific gene rearrangement which gives rise to the formation of several types of so-called RET/PTC chimeric genes. This lesions occur in almost 50% of papillary cancers and consist in the juxtaposition of the 3' or tyrosine kinase domain of the RET gene (which codes for a receptor protein not normally expressed in follicular thyroid cells) with the 5' domain of ubiquitously expressed genes, which provide the promoter and dimerization functions, necessary for the constitutive activation of RET/PTC proteins. Anaplastic carcinomas are frequently associated with mutations of the p53 tumor suppressor. Finally, point mutations of the RET gene are found in familial endocrine syndromes (FMTC; MEN2A and MEN2B), a common feature of which is the medullary thyroid carcinoma, a malignant tumor derived from parafollicular C-cells.
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PMID:Oncogenes and thyroid cancer. 1083 97

Activating mutations of the RET oncogene cause the inheritance of multiple endocrine neoplasia type 2 (MEN2). The RET pre-mRNA is spliced into several transcripts coding for multiple isoforms, including Ret9 and Ret51. When harboring activating mutations in the cytoplasmic region, the Ret51 protein displays a higher in vitro transforming efficiency as compared to the corresponding Ret9 isoform. We investigated whether a more transforming isoform was preferentially expressed in MEN2 tumors as compared to normal tissues or sporadic pheochromocytomas. By quantitative RNases protection assays, we measured the absolute abundance of the 3' splice variants in pheochromocytomas and in normal tissues. The proportion of RET51 transcripts was highly dispersed between tumors and normal tissues. In familial tumors the proportion of RET51 transcripts was significantly larger (48.1%) than in sporadic tumors (36.75%). This result suggests that the preferential expression of the Ret51 protein isoform, even though moderate, is a growth advantage for MEN2 tumors.
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PMID:Relative expression of the RET9 and RET51 isoforms in human pheochromocytomas. 1083 97


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