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)

Mutations in the fibroblast growth factor receptor (FGFR) gene family recently have been shown to underlie several hereditary disorders of bone development, with specific FGFR3 mutations causing achondroplasia (Ach) and thanatophoric dysplasia (TD). However, for none of these mutations has the defect in receptor function been demonstrated directly and, therefore, for none has the pathophysiological mechanism of the disease been defined. Using our established techniques for single-cell ratiometric real-time calcium image analysis, we defined the nature of the basic fibroblast growth factor (bFGF)-induced calcium signal in human diploid fibroblasts, and, in blinded studies, have analyzed the bFGF-induced signals from 18 independent fibroblast cell lines, including multiple lines from patients with known mutant alleles of FGFR3 and syndromes of Ach or TD. Control cells responded with transient increases in intracellular calcium, with many cells showing oscillatory calcium waves. Homozygous Ach cell lines failed to signal, whereas heterozygous Ach lines responded nearly normally. We observed heterogeneous signals in TD heterozygotes: the unresponsive lines all turned out to carry TD1 alleles, whereas all responsive lines had TD2 alleles. Since FGFR1, 2 and 3 receptors are known to be expressed in fibroblasts, our results suggest that specific mutant FGFR3 alleles can function in a dosage-dependent dominant-negative fashion to inactivate FGFR signaling.
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PMID:Mutations causing achondroplasia and thanatophoric dysplasia alter bFGF-induced calcium signals in human diploid fibroblasts. 915 42

Thanatophoric dysplasia (TD) is a lethal form of short-limb skeletal dysplasia that is associated with macrocephaly, and variably cloverleaf skull. Two types of TD are clinically recognized, TD1 and TD2, mainly distinguished by their radiographic characteristics. The differences between the two are principally observed in the femur, which appears curved in TD1, while it remains straight but with a proximal medial spike in TD2, and are a less severe overall affectation in TD2. Both types of TD are caused by mutations in different functional domains of the FGFR3 gene. However, whereas several mutations in the different domains of FGFR3 cause TD1, the K650E mutation involving the change of a lysine to glutamic acid ("Lys650Glu") has been found in all TD2 cases to date. Here we describe a newborn infant with TD2 associated with brain defects that have either been infrequently observed (encephalocele) or not hitherto described (holoprosencephaly). Based on recent studies, we consider encephaloceles described in TD to be pseudoencephaloceles, since they are secondary to the intracranial pressure generated by severe hydrocephaly and to severe cranial structural anomalies. Finally, to analyze the mechanisms of holoprosencephaly observed in the case described here, we include a concise review on the current understanding of how FGFs and their receptors are expressed in the rostral signaling center (particularly Fgf8). In addition, we evaluated recent observations that FGF ligands and receptors (including FGFR3) act in concert to organize the whole telencephalon activity, rather than independently patterning different areas.
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PMID:Thanatophoric dysplasia type II with encephalocele and semilobar holoprosencephaly: Insights into its pathogenesis. 2120 32

We previously determined that augmented EGFR tyrosine kinase (EGFRtk) impairs vascular function in type 2 diabetic mouse (TD2). Here we determined that EGFRtk causes vascular dysfunction through NADPH oxidase activity in TD2. Mesenteric resistance arteries (MRA) from C57/BL6 and db-/db- mice were mounted in a wired myograph and pre-incubated for 1h with either EGFRtk inhibitor (AG1478) or exogenous EGF. The inhibition of EGFRtk did not affect the contractile response to phenylephrine-(PE) and thromboxane-(U46619) or endothelium-dependent relaxation (EDR) to acetylcholine in MRA from control group. However, in TD2 mice, AG1478 reduced the contractile response to U46619, improved vasodilatation and reduced p22phox-NADPH expression, but had no effect on the contractile response to PE. The incubation of MRA with exogenous EGF potentiated the contractile response to PE in MRA from control and diabetic mice. However, EGF impaired the EDR and potentiated the vasoconstriction to U46619 only in the control group. Interestingly, NADPH oxidase inhibition in the presence of EGF restored the normal contraction to PE and improved the EDR but had no effect on the potentiated contraction to U46619. Vascular function improvement was associated with the rescue of eNOS and Akt and reduction in phosphorylated Rho-kinase, NOX4 mRNA levels, and NADPH oxidase activity. MRA from p47phox-/- mice incubated with EGF potentiated the contraction to U46619 but had no effect to PE or ACh responses. The present study provides evidence that augmented EGFRtk impairs vascular function by NADPH oxidase-dependent mechanism. Therefore, EGFRtk and oxidative stress should be potential targets to treat vascular dysfunction in TD2.
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PMID:Augmented EGF receptor tyrosine kinase activity impairs vascular function by NADPH oxidase-dependent mechanism in type 2 diabetic mouse. 2603 45