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)

Saethre-Chotzen syndrome is associated with haploinsufficiency of the basic-helix-loop-helix (bHLH) transcription factor TWIST1 and is characterized by premature closure of the cranial sutures, termed craniosynostosis; however, the mechanisms underlying this defect are unclear. Twist1 has been shown to play both positive and negative roles in mesenchymal specification and differentiation, and here we show that the activity of Twist1 is dependent on its dimer partner. Twist1 forms both homodimers (T/T) and heterodimers with E2A E proteins (T/E) and the relative level of Twist1 to the HLH inhibitor Id proteins determines which dimer forms. On the basis of the expression patterns of Twist1 and Id1 within the cranial sutures, we hypothesized that Twist1 forms homodimers in the osteogenic fronts and T/E heterodimers in the mid-sutures. In support of this hypothesis, we have found that genes regulated by T/T homodimers, such as FGFR2 and periostin, are expressed in the osteogenic fronts, whereas genes regulated by T/E heterodimers, such as thrombospondin-1, are expressed in the mid-sutures. The ratio between these dimers is altered in the sutures of Twist1+/- mice, favoring an increase in homodimers and an expansion of the osteogenic fronts. Of interest, the T/T to T/E ratio is greater in the coronal versus the sagittal suture, and this finding may contribute to making the coronal suture more susceptible to fusion due to TWIST haploinsufficiency. Importantly, we were able to inhibit suture fusion in Twist1+/- mice by modulating the balance between these dimers toward T/E formation, by either increasing the expression of E2A E12 or by decreasing Id expression. Therefore, we have identified dimer partner selection as an important mediator of Twist1 function and provide a mechanistic understanding of craniosynostosis due to TWIST haploinsufficiency.
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PMID:Twist1 dimer selection regulates cranial suture patterning and fusion. 1650 19

Saethre-Chotzen syndrome is caused by mutations in the TWIST gene on chromosome 7p21.2. However, Muenke et al. [(1997); Am J Hum Genet 91: 555-564] described a new subgroup carrying the Pro250Arg mutation in the fibroblast growth factor receptor (FGFR) 3 gene on chromosome 4p16. Uni or bicoronal synostosis appears to be the main clinical finding in both syndromes. We observed trigonocephaly as a new manifestation in Muenke syndrome. As a consequence we advise to routinely perform mutation analysis of the FGFR1, 2, and 3 genes in children with non-syndromic trigonocephaly.
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PMID:Trigonocephaly in Muenke syndrome. 1703 34

Craniosynostosis, the premature fusion of one or more cranial sutures, affects 1 in 2,500 live births. Isolated single-suture fusion is most prevalent, with sagittal synostosis occurring in 1/5,000 live births. The etiology of isolated (nonsyndromic) single-suture craniosynostosis is largely unknown. In syndromic craniosynostosis, there is a highly nonrandom pattern of causative autosomal dominant mutations involving TWIST1 and fibroblast growth factor receptors (FGFRs). Prior to our study, there were no published TWIST1 mutations in the anti-osteogenic C-terminus, recently coined the TWIST Box, which binds and inhibits RUNX2 transactivation. RUNX2 is the principal master switch for osteogenesis. We performed mutational analysis on 164 infants with isolated, single-suture craniosynostosis for mutations in TWIST1, the IgIIIa exon of FGFR1, the IgIIIa and IgIIIc exons of FGFR2, and the Pro250Arg site of FGFR3. We identified two patients with novel TWIST Box mutations: one with isolated sagittal synostosis and one with isolated coronal synostosis. Kress et al. [2006] reported a TWIST Box "nondisease-causing polymorphism" in a patient with isolated sagittal synostosis. However, compelling evidence suggests that their and our sequence alterations are pathogenic: (1) a mouse with a mutation of the same residue as our sagittal synostosis patient developed sagittal synostosis, (2) mutation of the same residue precluded TWIST1 interaction with RUNX2, (3) each mutation involved nonconservative amino acid substitutions in highly conserved residues across species, and (4) control chromosomes lacked TWIST Box sequence alterations. We suggest that genetic testing of patients with isolated sagittal or coronal synostosis should include TWIST1 mutational analysis.
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PMID:Isolated sagittal and coronal craniosynostosis associated with TWIST box mutations. 1734 69

Pathogenic mutations in FGFR2 and TWIST genes are detected in the majority of individuals with Crouzon, Pfeiffer, Apert, and Saethre-Chotzen syndromes. In contrast, mutations have been identified rarely in cases of nonsyndromic, single suture craniosynostosis. Recently, two studies confirming somatic mosaicism with local expression of an FGFR mutation have been reported. This study investigates whether somatic mosaicism could account for nonsyndromic, single suture craniosynostosis. Eight individuals with single suture craniosynostosis who were negative for known mutations in FGFR1-3 and TWIST after screening in their leucocyte DNA were tested for the presence of pathogenic mutations in suture cell-derived DNA. Five had sagittal synostosis, two had metopic synostosis, and the other unicoronal synostosis. Osteoprogenitor cells from surgically excised fusing sutures and an adjacent open suture were cultured. DNA from the cultured cells grown to passage 3 was then examined for underlying FGFR and TWIST mutations. No mutations within the exons of the FGFR or TWIST genes studied were identified in any suture cells. This study found no evidence to support the notion that mosaicism for FGFR or TWIST mutations, normally associated with syndromal forms of craniosynostosis, occur in single suture craniosynostosis. Thus, any underlying genetic defects must occur in regions outside those normally implicated in syndromal craniosynostosis, or this disorder could arise as a consequence of some other epigenetic modification.
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PMID:Somatic FGFR and TWIST mutations are not a common cause of isolated nonsyndromic single suture craniosynostosis. 1741 80

Extracellular signal-regulated kinases (ERKs) activity is regulated by MAPK/ERK kinases (MEKs), which phosphorylate the regulatory Tyr and Thr residues in ERKs activation loop, and by various phosphatases that remove the incorporated phosphates. Although the role of the phosphorylated residues in the activation loop of ERKs is well studied, much less is known about the role of other residues within this loop. Here we substituted several residues within amino acids 173-177 of ERK2 and studied their role in ERK2 phosphorylation, substrate recognition, and subcellular localization. We found that substitution of residues 173-175 and particularly Pro(174) to alanines reduces the EGF-induced ERK2 phosphorylation, without modifying its in vitro phosphorylation by MEK1. Examining the ability of these mutants to be dephosphorylated revealed that 173-5A mutants are hypersensitive to phosphatases, indicating that these residues are important for setting the phosphorylation/dephosphorylation balance of ERKs. In addition, 173-5A mutants reduced ERK2 activity toward Elk-1, without affecting the activity of ERK2 toward MBP, while substitution of residues 176-8 decreased ERK2 activity toward both substrates. Substitution of Asp(177) to alanine increased nuclear localization of the construct in MEK1-overexpressing cells, suggesting that this residue together with His(176) is involved in the dissociation of ERK2 from MEKs. Combining CRS/CD motif and the activation loop mutations revealed that these two regions cooperate in determining the net phosphorylation of ERK2, but the role of the CRS/CD motif predominates that of the activation loop residues. Thus, we show here that residues 173-177 of ERK2 join other regulatory regions of ERKs in governing ERK activity.
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PMID:Role of non-phosphorylated activation loop residues in determining ERK2 dephosphorylation, activity, and subcellular localization. 1759 65

Dysregulated cell growth or differentiation due to misexpression of developmental critical factors seems to be a decisive event in oncogenesis. As osteosarcomas are histologically defined by malignant osteoblasts producing an osteoid component, we prospected in pediatric osteosarcomas treated with OS94 protocol the genomic status of several genes implied in ossification processes. In 91 osteosarcoma cases, we focused on the analysis of the fibroblast growth factor receptors (FGFRs) TWIST, APC, and MET by allelotyping, real-time quantitative polymerase chain reaction, gene sequencing, and protein polymorphism study. Our study supports the frequent role of TWIST, APC, and MET as osteosarcoma markers (50%, 62%, and 50%, respectively). TWIST and MET were mainly found to be deleted, and no additional APC mutation was identified. Surprisingly, FGFRs are abnormal in only < 30%. Most of these factors and their abnormalities seem to be linked more or less to one clinical subgroup, but the most significant correlation is the link of MET, TWIST, and APC abnormalities to a worse outcome and their combination within abnormal tumors. A wider cohort is mandatory to define more robust molecular conclusions, but these results are to be considered as the beginning of a more accurate basis for diagnosis, in search of targeted therapies, and to further characterize prognostic markers.
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PMID:Involvement of MET/TWIST/APC combination or the potential role of ossification factors in pediatric high-grade osteosarcoma oncogenesis. 1778 87

Aberrant epidermal growth factor receptor (EGFR) signaling is a major cause of tumor progression and metastasis; the underlying mechanisms, however, are not well understood. In particular, it remains elusive whether deregulated EGFR pathway is involved in epithelial-mesenchymal transition (EMT), an early event that occurs during metastasis of cancers of an epithelial origin. Here, we show that EGF induces EGFR-expressing cancer cells to undergo a transition from the epithelial to the spindle-like mesenchymal morphology. EGF reduced E-cadherin expression and increased that of mesenchymal proteins. In search of a downstream mediator that may account for EGF-induced EMT, we focused on transcription repressors of E-cadherin, TWIST, SLUG, and Snail and found that cancer cells express high levels of TWIST and that EGF enhances its expression. EGF significantly increases TWIST transcripts and protein in EGFR-expressing lines. Forced expression of EGFR reactivates TWIST expression in EGFR-null cells. TWIST expression is suppressed by EGFR and Janus-activated kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) inhibitors, but not significantly by those targeting phosphoinositide-3 kinase and MEK/ERK. Furthermore, constitutively active STAT3 significantly activates the TWIST promoter, whereas the JAK/STAT3 inhibitor and dominant-negative STAT3 suppressed TWIST promoter. Deletion/mutation studies further show that a 26-bp promoter region contains putative STAT3 elements required for the EGF-responsiveness of the TWIST promoter. Chromatin immunoprecipitation assays further show that EGF induces binding of nuclear STAT3 to the TWIST promoter. Immunohistochemical analysis of 130 primary breast carcinomas indicates positive correlations between non-nuclear EGFR and TWIST and between phosphorylated STAT3 and TWIST. Together, we report here that EGF/EGFR signaling pathways induce cancer cell EMT via STAT3-mediated TWIST gene expression.
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PMID:Epidermal growth factor receptor cooperates with signal transducer and activator of transcription 3 to induce epithelial-mesenchymal transition in cancer cells via up-regulation of TWIST gene expression. 1790 10

Non syndromic cleft lip and palate (CLP) is the most frequent human malformation. CLP is of complex inheritance and at least twenty contributing chromosomal regions have been identified by linkage studies. On the other hand, mutations in several genes such as TWIST and FGFR2 result in syndromic cranio-facial abnormalities of highly variable range. It is our hypothesis that some mutations at TWIST might contribute to CLP in absence of other dysmorphic features. Thus, DNA biopsies of patients with non syndromic CLP are collected and prepared to search for allelic variations or mutations at TWIST. This study should contribute to improve the classification of facial malformations relative to gene, to help to a better understanding of the inheritance pattern of this pathology, to help to genetic counselling for some cases aiming at the prevention of genetic disease. This project is based on a close cooperation between the Orthodontic Department, the Paediatric Surgery Department and the Center for Clinical Investigation (University Hospital in Strasbourg), in a joint project with an academic research laboratory, expert in molecular biology and genetics.
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PMID:[Genetic origin of non-syndromic cleft lip and palate. TWIST, a candidate gene? Research protocol]. 1808 15

Previous reports have implicated epithelial-mesenchymal transition (EMT) as a major cause of cancer. TWIST, a novel zinc finger transcription factor, was suggested to be an important inducer of EMT and therefore be involved in different phases of tumorigenicity. However, whether TWIST suppression could increase chemosensitivity of cancer cells to chemotherapeutic agent remains unclear. In the present study, we utilized RNA interference to knockdown TWIST expression in A549 cells and further assessed the cell viability and apoptosis as well as possible MAPKs and mitochondrial pathways. The data showed that TWIST depletion significantly sensitized A549 cells to cisplatin by inducing activation of JNK/mitochondrial pathway but not ERK and p-38 pathways, suggesting critical roles of TWIST in A549 cell chemoresistance to cisplatin and raising the possibility of TWIST depletion as a promising approach to lung cancer therapy.
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PMID:Short interfering RNA directed against TWIST, a novel zinc finger transcription factor, increases A549 cell sensitivity to cisplatin via MAPK/mitochondrial pathway. 1833 24

We report on clinical and molecular findings of two brothers that both presented with sagittal craniosynostosis, hydrocephalus, Chiari I malformation, blepharophimosis, small low-set ears, hypoplastic philtrum, radioulnar synostosis, kidney malformation, and hypogenitalism. Their father presented mild brachydactyly. Conventional cytogenetic and array CGH screening did not show any chromosomal gains or losses. Furthermore, molecular genetic screening of genes involved in different craniosynostosis syndromes, namely FGFR1, FGFR2, FGFR3, TWIST, RECQL4, and POR genes failed to detect any mutations in genomic DNA. The unique range of clinical manifestations in these two patients and the negative findings of the molecular genetic screening suggest the hypothesis of a previously unrecognized syndrome.
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PMID:Craniosynostosis, hydrocephalus, Chiari I malformation and radioulnar synostosis: probably a new syndrome. 1902 12


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