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)

The mRNA levels of RET and GDNFR-alpha were studied in the spinal cord of patients with amyotrophic lateral sclerosis (ALS) by reverse transcription followed by polymerase chain reaction (RT-PCR) and in situ hybridization (ISH). Semiquantitative RT-PCR analysis revealed that RET mRNA levels in the ALS spinal cord anterior horn were reduced to one fifth of controls in proportion to motor neuron loss, whereas GDNFR-alpha mRNA was unchanged. ISH analysis showed that RET mRNA was expressed in the anterior horn motor neurons of the spinal cord, but GDNFR-alpha mRNA was expressed widely in the spinal cord neurons and glial cells. The RET mRNA levels, measured using a CCD image analyzer, were substantially preserved in individual motor neurons of ALS, but varied among those neurons. Relatively high levels of RET mRNA were observed in a certain population of atrophic neurons. On the other hand, the GDNFR-alpha mRNA levels in the motor neurons were similar in ALS and controls. In addition, the RET protein was also well expressed in individual motor neurons in ALS. These results indicate that GDNF receptor expression persists at mRNA and protein levels in the degenerating motor neurons in ALS, supporting the view that GDNF is a candidate for therapeutic approach to ALS.
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PMID:Expression of GDNF receptor (RET and GDNFR-alpha) mRNAs in the spinal cord of patients with amyotrophic lateral sclerosis. 1002 33

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

We report a boy with truncus arteriosus, dysmorphic features, developmental delay, passing hypotonia, short segment Hirschsprung disease (HSCR), and paroxysmal hypoventilation. FISH analysis showed an interstitial deletion in chromosome band 22q11.2 coinciding with the deletions found in DiGeorge syndrome and velocardiofacial syndrome. Mutation scanning of RET, GDNF, EDNRB, and EDN3, genes associated with Hirschsprung disease, showed no aberrations. Since we know of two more patients with velocardiofacial syndrome and HSCR, we hypothesise that a gene responsible for proper development of the enteric nervous system may be included in the 22q11.2 region.
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PMID:A Hirschsprung disease locus at 22q11? 1020 49

Hirschsprung's disease, affecting one in 5000 live newborns, is the most common cause of neonatal intestinal obstruction. The obstruction or, later in life, constipation arises from the lack of enteric ganglia in the hindgut, thus resulting in poor coordination of peristalsis. Mutations in Hirschsprung patients have so far been reported in five genes associated in two different receptor-ligand systems, RET-GDNF/NTN and EDNRB-EDN-3, and an additional gene with yet unknown precise function, SOX10. We report the results of single-stranded conformation polymorphism screening of the endothelin-3 gene in a Swedish population-based material of 66 sporadic and nine familial Hirschsprung's disease cases. We have found a novel heterozygous mutation in exon 2, c.262insG, in a patient with sporadic short segment Hirschsprung's disease without any Waardenburg features. This frameshift results in a premature stop two codons further on. Because this stop is introduced 5' of the biologically active protein, this mutation can hence be predicted to result in haplo-insufficiency.
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PMID:A heterozygous frameshift mutation in the endothelin-3 (EDN-3) gene in isolated Hirschsprung's disease. 1023 70

During embryogenesis, two different transmembrane receptors, Ret and Ednrb, together with their ligands, respective, GDNF and endothelin-3, are involved in the migration and differentiation of enteric ganglion cells, sympathetic neurons and melanocytes from the neural crest. Mutations in these genes have been found in a number of human and murine neurocristopathies, including Hirschsprung's disease. RET and GDNF knockouts suggest that they are involved in a correct autonomic nervous system formation. The aim of this study is the evaluation of the autonomic nervous system in patients with Hirschsprung's disease. Seventeen children (mean age: 8.6 years) with Hirschsprung's disease and 19 age- and sex-matched control children (mean age: 9.9 years) underwent pupillary and cardiovascular testing of sympathetic adrenergic and cholinergic function and cardiovagal cholinergic function. Seven of 17 patients with Hirschsprung's disease were affected by autonomic dysfunction. Three of seven patients had evidence of sympathetic denervation, two showed a parasympathetic dysfunction, whereas the remaining two had dysfunction of both sympathetic and parasympathetic tests. Our data in a small number of patients with Hirschsprung's disease show that a subset of these patients exhibits measurable autonomic dysfunction. A RET mutation has been found in one of them. As for the absence of the enteric ganglion cells, autonomic dysfunction in these subjects seems to be polygenic.
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PMID:Autonomic dysfunction in children with Hirschsprung's disease. 1023 4

The mRNA expression levels of GDNF, GDNFR-alpha and RET were examined in the muscles of amyotrophic lateral screlosis (ALS) and X-linked spinal and bulbar muscular atrophy (SBMA). GDNF mRNA levels were significantly elevated to variable extent in the diseased muscles compared to control muscles, although they were not specific to the type of the diseases. The diseased muscles also have a different expression pattern of GDNF mRNA isoforms from controls. GDNF mRNA expression, however, tended to reduce in advanced muscle pathology. On the other hand, GDNFR-alpha mRNA levels were not changed significantly on expression levels in the diseased muscles. In situ hybridization study revealed that GDNF and GDNFR-alpha mRNAs were localized in subsarcolemmal space of muscle cells. RET mRNA was not detected in control nor diseased muscles. These results suggest that the elevated muscle GDNF acts as a trophic signal for motor neurons of motor neuron diseases, implying a possible therapeutic implication of GDNF to this type of diseases.
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PMID:Expression of GDNF and GDNFR-alpha mRNAs in muscles of patients with motor neuron diseases. 1044 63

To study possible effects of physical training on the expression of neurotrophic factors and their receptors in the brain, we used a rat strain (spontaneously hypertensive rat, SHR), known to spontaneously run up to 20 km/night. We show that such long-distance running affects the brain-derived neurotrophic factor (BDNF) and TrkB system in hippocampus, and in particular that abrupt deprivation of habitual running leads to long-lasting decreases of BDNF/TrkB expression in hippocampus. Quantitative in situ hybridization demonstrates that running increases the expression of mRNA coding for BDNF and its high affinity receptor TrkB in hippocampus in a running length dependent manner. In addition, we show that an abrupt interruption of prolonged spontaneous exercise decrease expression of mRNA encoding BDNF and TrkB in certain hippocampal areas and that this decrease lasts at least 10 days. This down-regulation was most prominent in medial cornu ammonis 3 (CA3M). Several other trophic factors and receptors were investigated, including NGF, NT3, GDNF, trkC and p75. For these other probes investigated, no robust changes in mRNA expression were noted. Areas examined included sensorimotor cortex and hippocampus. For RET, p75, NT3, TrkB and BDNF we also examined the spinal cord without detecting any robust changes. We conclude that spontaneous running as well as its abrupt termination, leads to area-specific and trophic factor-specific changes in hippocampus.
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PMID:Deprived of habitual running, rats downregulate BDNF and TrkB messages in the brain. 1051 54

Pheochromocytomas are tumors originating from chromaffin cells, the large majority of which are sporadic neoplasms. The genetic and molecular events determining their tumorigenesis continue to remain unknown. On the other hand, RET germ-line mutations cause the inheritance of familial tumors in multiple endocrine neoplasia (MEN)-2 diseases, which account for a minority of pheochromocytomas. We investigated the expression of the RET gene in 14 sporadic tumors harboring no activating mutations. A subset of highly RET-expressing tumors (50%) could be distinguished. They showed RET transcript, protein amounts as well as Ret-associated phosphotyrosine levels similar to those measured in MEN-2A-associated pheochromocytomas. We also determined the GDNF and GDNF family receptor alpha (GFRalpha)-1 transcript levels in tumors and in normal tissues. Whereas the GFRalpha-1 transcripts were detected at similar levels in normal tissues and in tumors, GDNF was frequently found expressed in sporadic tumors at levels several times higher than in controls. These results led us to propose the existence of an autocrine or paracrine loop leading to chronic stimulation of the Ret signaling pathway, which could participate in the pathogenesis of a number of sporadic pheochromocytomas.
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PMID:High levels of tyrosine phosphorylated proto-ret in sporadic phenochromocytomas. 1072

Wilms' tumor (WT) is caused by abnormal development of embryonal kidney cells. WT cells are frequently affected by deletions or functional inactivation of maternal alleles at chromosome 11p15, which indicates that the loss of maternally expressed genes in this region plays an important role in WT pathogenesis. Maternally expressed genes indeed exist within an imprinted region at 11p15.5. Among these, BWR1C is highly expressed in fetal but not in adult kidney, which suggests that it may fulfil an important role in kidney development. Here, we demonstrate that the lack of BWR1C expression is common in WT. Its homology with the proapoptotic gene TDAG51 suggests that the loss of BWR1C expression may be relevant in WT development. In addition, the analysis of the expression of other 11p15 imprinted genes and kidney-developmentally regulated genes indicates that IGF2 overexpression, inappropriate coexpression of RET and GDNF and, in some cases, down-regulation of CDKN1C may also play an important role in the pathogenesis of WT. Our results add new elements to the understanding of the biological basis of WT, which may have implications for WT diagnosis and therapy.
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PMID:Abnormal RNA expression of 11p15 imprinted genes and kidney developmental genes in Wilms' tumor. 1074 16

The GDNF family ligands (GFLs: GDNF, neurturin, persephin, and artemin) signal through RET and a gly-cosyl-phosphatidylinositol (GPI)-anchored coreceptor (GFRalpha1-alpha4) that binds ligand with high affinity and provides specificity. The importance of the GPI anchor is not fully understood; however, GPI-linked proteins cluster into lipid rafts, structures that may represent highly specialized signaling organelles. Here, we report that GPI-anchored GFRalpha1 recruits RET to lipid rafts after GDNF stimulation and results in RET/Src association. Disruption of RET localization using either transmembrane-anchored or soluble GFRalpha1 results in RET phosphorylation, but GDNF-induced intracellular signaling events are markedly attenuated as are neuronal differentiation and survival responses. Therefore, proper membrane localization of RET via interaction with a raft-localized, GPI-linked coreceptor is of fundamental importance in GFL signaling.
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PMID:GFRalpha-mediated localization of RET to lipid rafts is required for effective downstream signaling, differentiation, and neuronal survival. 1077 29


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