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Träfflista för sökning "WFRF:(Wolfstetter Georg) "

Sökning: WFRF:(Wolfstetter Georg)

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1.
  • Guan, Jikui, et al. (författare)
  • Anaplastic lymphoma kinase L1198F and G1201E mutations identified in anaplastic thyroid cancer patients are not ligand-independent.
  • 2017
  • Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 2017:8, s. 11566-11578
  • Tidskriftsartikel (refereegranskat)abstract
    • Activating mutations in full length anaplastic lymphoma kinase (ALK) have been reported in neuroblastoma and in anaplastic thyroid cancer. ALK-L1198F and ALK-G1201E mutations were originally identified in anaplastic thyroid cancer (ATC) and characterized as constitutively activating mutations. In this study, we employed in vitro cell culture assays together with biochemical and in vivo Drosophila analyses to characterize their sensitivity to either activation by the FAM150A (AUG-β) and FAM150B (AUG-α) ALK ligands or inhibition by ALK inhibitors. Here we report that neither ALK-L1198F nor ALK-G1201E mutations result in ligand independent gain-of-function (GOF) activity in either in vitro biochemical analysis or the various model systems employed. ALK-L1198F is activated by the FAM150 (AUG) ligands and its ligand-dependant activity is similar to the wild type full length ALK receptor. ALK-G1201E is only very weakly activated by the FAM150 (AUG) ligands, most likely due to impaired protein stability. We conclude that neither ALK-L1198F nor ALK-G1201E displays ligand independent kinase activity, with ALK-L1198F belonging to the class of ligand dependent ALK mutations which are not constitutively active but that responds to ligand activation, while the ALK-G1201E mutation generates an unstable receptor with very low levels of kinase activity.
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2.
  • Guan, Jikui, et al. (författare)
  • FAM150A and FAM150B are activating ligands for anaplastic lymphoma kinase
  • 2015
  • Ingår i: eLIFE. - Cambridge : eLife Sciences Publications. - 2050-084X. ; 4
  • Tidskriftsartikel (refereegranskat)abstract
    • Aberrant activation of anaplastic lymphoma kinase (ALK) has been described in a range of human cancers, including non-small cell lung cancer and neuroblastoma (Hallberg and Palmer, 2013). Vertebrate ALK has been considered to be an orphan receptor and the identity of the ALK ligand(s) is a critical issue. Here we show that FAM150A and FAM150B are potent ligands for human ALK that bind to the extracellular domain of ALK and in addition to activation of wild-type ALK are able to drive 'superactivation' of activated ALK mutants from neuroblastoma. In conclusion, our data show that ALK is robustly activated by the FAM150A/B ligands and provide an opportunity to develop ALK-targeted therapies in situations where ALK is overexpressed/activated or mutated in the context of the full length receptor.
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3.
  • Mendoza-Garcia, Patricia, 1988-, et al. (författare)
  • The Zic family homologue Odd-paired regulates Alk expression in Drosophila.
  • 2017
  • Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404 .- 1553-7390. ; 13:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The Anaplastic Lymphoma Kinase (Alk) receptor tyrosine kinase (RTK) plays a critical role in the specification of founder cells (FCs) in the Drosophila visceral mesoderm (VM) during embryogenesis. Reporter gene and CRISPR/Cas9 deletion analysis reveals enhancer regions in and upstream of the Alk locus that influence tissue-specific expression in the amnioserosa (AS), the VM and the epidermis. By performing high throughput yeast one-hybrid screens (Y1H) with a library of Drosophila transcription factors (TFs) we identify Odd-paired (Opa), the Drosophila homologue of the vertebrate Zic family of TFs, as a novel regulator of embryonic Alk expression. Further characterization identifies evolutionarily conserved Opa-binding cis-regulatory motifs in one of the Alk associated enhancer elements. Employing Alk reporter lines as well as CRISPR/Cas9-mediated removal of regulatory elements in the Alk locus, we show modulation of Alk expression by Opa in the embryonic AS, epidermis and VM. In addition, we identify enhancer elements that integrate input from additional TFs, such as Binou (Bin) and Bagpipe (Bap), to regulate VM expression of Alk in a combinatorial manner. Taken together, our data show that the Opa zinc finger TF is a novel regulator of embryonic Alk expression.
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4.
  • Mendoza, Patricia, et al. (författare)
  • DamID transcriptional profiling identifies the Snail/Scratch transcription factor Kahuli as an Alk target in the Drosophila visceral mesoderm
  • 2021
  • Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 148:23
  • Tidskriftsartikel (refereegranskat)abstract
    • Development of the Drosophila visceral muscle depends on Anaplastic Lymphoma Kinase (Alk) receptor tyrosine kinase (RTK) signaling, which specifies founder cells (FCs) in the circular visceral mesoderm (VM). Although Alk activation by its ligand Jelly Belly (Jeb) is well characterized, few target molecules have been identified. Here, we used targeted DamID (TaDa) to identify Alk targets in embryos overexpressing Jeb versus embryos with abrogated Alk activity, revealing differentially expressed genes, including the Snail/Scratch family transcription factor Kahuli (Kah). We confirmed Kah mRNA and protein expression in the VM, and identified midgut constriction defects in Kah mutants similar to those of pointed (pnt). ChIP and RNA-Seq data analysis defined a Kah target-binding site similar to that of Snail, and identified a set of common target genes putatively regulated by Kah and Pnt during midgut constriction. Taken together, we report a rich dataset of Alk-responsive loci in the embryonic VM and functionally characterize the role of Kah in the regulation of embryonic midgut morphogenesis.
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5.
  • Pfeifer, Kathrin, et al. (författare)
  • Identification and characterization of a twist ortholog in the polychaete annelid Platynereis dumerilii reveals mesodermal expression of Pdu-twist
  • 2013
  • Ingår i: Development, Genes and Evolution. - : Springer Berlin/Heidelberg. - 0949-944X .- 1432-041X. ; 223:5, s. 319-328
  • Tidskriftsartikel (refereegranskat)abstract
    • The basic helix-loop-helix transcription factor twist plays a key role during mesoderm development in Bilateria. In this study, we identified a twist ortholog in the polychaete annelid Platynereis dumerilii and analyze its expression during larval development, postlarval growth up to the adult stage, and caudal regeneration after amputation of posterior segments. At late larval stages, Pdu-twist is expressed in the mesodermal anlagen and in developing muscles. During adulthood and caudal regeneration, Pdu-twist is expressed in the posterior growth zone, in mesodermal cells within the newly forming segments and budding parapodia. Our results indicate that Pdu-twist is involved in mesoderm formation during larval development, posterior growth, and caudal regeneration.
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6.
  • Pfeifer, Kathrin, et al. (författare)
  • Patient-associated mutations in Drosophila Alk perturb neuronal differentiation and promote survival.
  • 2022
  • Ingår i: Disease models & mechanisms. - : The Company of Biologists. - 1754-8411 .- 1754-8403. ; 15:8
  • Tidskriftsartikel (refereegranskat)abstract
    • Activating anaplastic lymphoma kinase (ALK) receptor tyrosine kinase (RTK) mutations occur in pediatric neuroblastoma and are associated with poor prognosis. To study ALK-activating mutations in a genetically controllable system, we employed CRIPSR/Cas9, incorporating orthologs of the human oncogenic mutations ALKF1174L and ALKY1278S in the Drosophila Alk locus. AlkF1251L and AlkY1355S mutant Drosophila exhibited enhanced Alk signaling phenotypes, but unexpectedly depended on the Jelly belly (Jeb) ligand for activation. Both AlkF1251L and AlkY1355S mutant larval brains displayed hyperplasia, represented by increased numbers of Alk-positive neurons. Despite this hyperplasic phenotype, no brain tumors were observed in mutant animals. We showed that hyperplasia in Alk mutants was not caused by significantly increased rates of proliferation, but rather by decreased levels of apoptosis in the larval brain. Using single-cell RNA sequencing, we identified perturbations during temporal fate specification in AlkY1355S mutant mushroom body lineages. These findings shed light on the role of Alk in neurodevelopmental processes and highlight the potential of Alk-activating mutations to perturb specification and promote survival in neuronal lineages. This article has an associated First Person interview with the first author of the paper.
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7.
  • Popichenko, Dmitry, et al. (författare)
  • Jeb/Alk signalling regulates the Lame duck GLI family transcription factor in the Drosophila visceral mesoderm
  • 2013
  • Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 140:15, s. 3156-3166
  • Tidskriftsartikel (refereegranskat)abstract
    • The Jelly belly (Jeb)/Anaplastic Lymphoma Kinase (Alk) signalling pathway regulates myoblast fusion in the circular visceral mesoderm (VM) of Drosophila embryos via specification of founder cells. However, only a limited number of target molecules for this pathway are described. We have investigated the role of the Lame Duck (Lmd) transcription factor in VM development in relationship to Jeb/Alk signal transduction. We show that Alk signalling negatively regulates Lmd activity post-transcriptionally through the MEK/MAPK (ERK) cascade resulting in a relocalisation of Lmd protein from the nucleus to cytoplasm. It has previously been shown that downregulation of Lmd protein is necessary for the correct specification of founder cells. In the visceral mesoderm of lmd mutant embryos, fusion-competent myoblasts seem to be converted to 'founder-like' cells that are still able to build a gut musculature even in the absence of fusion. The ability of Alk signalling to downregulate Lmd protein requires the N-terminal 140 amino acids, as a Lmd(141-866) mutant remains nuclear in the presence of active ALK and is able to drive robust expression of the Lmd downstream target Vrp1 in the developing VM. Our results suggest that Lmd is a target of Jeb/Alk signalling in the VM of Drosophila embryos.
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8.
  • Uçkun, Ezgi, et al. (författare)
  • BioID-Screening Identifies PEAK1 and SHP2 as Components of the ALK Proximitome in Neuroblastoma Cells
  • 2021
  • Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836. ; 433:19
  • Tidskriftsartikel (refereegranskat)abstract
    • Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) that is mutated in approximately 10% of pediatric neuroblastoma (NB). To shed light on ALK-driven signaling processes, we employed BioID-based in vivo proximity labeling to identify molecules that interact intracellularly with ALK. NBderived SK-N-AS and SK-N-BE(2) cells expressing inducible ALK-BirA* fusion proteins were generated and stimulated with ALKAL ligands in the presence and absence of the ALK tyrosine kinase inhibitor (TKI) lorlatinib. LC/MS-MS analysis identified multiple proteins, including PEAK1 and SHP2, which were validated as ALK interactors in NB cells. Further analysis of the ALK-SHP2 interaction confirmed that the ALK-SHP2 interaction as well as SHP2-Y542 phosphorylation was dependent on ALK activation. Use of the SHP2 inhibitors, SHP099 and RMC-4550, resulted in inhibition of cell growth in ALK-driven NB cells. In addition, we noted a strong synergistic effect of combined ALK and SHP2 inhibition that was specific to ALK-driven NB cells, suggesting a potential therapeutic option for ALK-driven NB. (C) 2021 The Author(s). Published by Elsevier Ltd.
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9.
  • Uçkun, Ezgi, et al. (författare)
  • In vivo Characterization of Endogenous Protein Interactomes in Drosophila Larval Brain, Using a CRISPR/Cas9-based Strategy and BioID-based Proximity Labeling
  • 2022
  • Ingår i: Bio-protocol. - 2331-8325. ; 12:13
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding protein-protein interactions (PPIs) and interactome networks is essential to reveal molecular mechanisms mediating various cellular processes. The most common method to study PPIs in vivo is affinity purification combined with mass spectrometry (AP-MS). Although AP-MS is a powerful method, loss of weak and transient interactions is still a major limitation. Proximity labeling (PL) techniques have been developed as alternatives to overcome these limitations. Proximity-dependent biotin identification (BioID) is one such widely used PL method. The first-generation BiolD enzyme BirA*, a promiscuous bacterial biotin ligase, has been effectively used in cultured mammalian cells; however, relatively slow enzyme kinetics make it less effective for temporal analysis of protein interactions. In addition, BirA* exhibits reduced activity at temperatures below 37 degrees C, further restricting its use in intact organisms cultured at lower optimal growth temperatures (e.g., Drosophila melanogaster). TurboID, miniTurbo, and BirA*-G3 are next generation BirA* variants with improved catalytic activity, allowing investigators to use this powerful tool in model systems such as flies. Here, we describe a detailed experimental workflow to efficiently identify the proximal proteome (proximitome) of a protein of interest (POI) in the Drosophila brain using CRISPR/Cas9-induced homology-directed repair (HDR) strategies to endogenously tag the POI with next generation BioID enzymes.
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10.
  • Uçkun, Ezgi, et al. (författare)
  • In vivo Profiling of the Alk Proximitome in the Developing Drosophila Brain
  • 2021
  • Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836. ; 433:23
  • Tidskriftsartikel (refereegranskat)abstract
    • Anaplastic lymphoma kinase (Alk) is an evolutionary conserved receptor tyrosine kinase belonging to the insulin receptor superfamily. In addition to its well-studied role in cancer, numerous studies have revealed that Alk signaling is associated with a variety of complex traits such as: regulation of growth and metabolism, hibernation, regulation of neurotransmitters, synaptic coupling, axon targeting, decision making, memory formation and learning, alcohol use disorder, as well as steroid hormone metabolism. In this study, we used BioID-based in vivo proximity labeling to identify molecules that interact with Alk in the Drosophila central nervous system (CNS). To do this, we used CRISPR/Cas9 induced homology-directed repair (HDR) to modify the endogenous Alk locus to produce first and next generation Alk::BioID chimeras. This approach allowed identification of Alk proximitomes under physiological conditions and without overexpression. Our results show that the next generation of BioID proteins (TurbolD and miniTurbo) outperform the first generation BirA* fusion in terms of labeling speed and efficiency. LC-MS3-based BioID screening of Alk(TurbolD) and Alk(miniTurbo) larval brains revealed an extensive neuronal Alk proximitome identifying numerous potential components of Alk signaling complexes. Validation of Alk proximitome candidates further revealed co-expression of Stardust (Sdt), Discs large 1 (Dlg1), Syntaxin (Syx) and Rugose (Rg) with Alk in the CNS and identified the protein-tyrosine-phosphatase Corkscrew (Csw) as a modulator of Alk signaling. (C) 2021 The Author(s). Published by Elsevier Ltd.
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