0000000000943686

AUTHOR

Rene Ramseger

showing 3 related works from this author

Transmembrane form agrin-induced process formation requires lipid rafts and the activation of Fyn and MAPK.

2009

Overexpression or clustering of the transmembrane form of the extracellular matrix heparan sulfate proteoglycan agrin (TM-agrin) induces the formation of highly dynamic filopodia-like processes on axons and dendrites from central and peripheral nervous system-derived neurons. Here we show that the formation of these processes is paralleled by a partitioning of TM-agrin into lipid rafts, that lipid rafts and transmembrane-agrin colocalize on the processes, that extraction of lipid rafts with methyl-β-cyclodextrin leads to a dose-dependent reduction of process formation, that inhibition of lipid raft synthesis prevents process formation, and that the continuous presence of lipid rafts is requ…

MAPK/ERK pathwayanimal structuresMAP Kinase Signaling SystemChick EmbryoBiologyProto-Oncogene Proteins c-fynBiochemistryExtracellular matrixFYNMembrane MicrodomainsMolecular Basis of Cell and Developmental BiologyAnimalsSrc family kinasePseudopodiaPhosphorylationMolecular BiologyLipid raftCells CulturedMitogen-Activated Protein Kinase KinasesAgrinDose-Response Relationship Drugbeta-CyclodextrinsCell BiologyDendritesTransmembrane proteinAxonsCell biologyEnzyme Activationnervous systemPhosphorylationlipids (amino acids peptides and proteins)ChickensThe Journal of biological chemistry
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The Process-inducing Activity of Transmembrane Agrin Requires Follistatin-like Domains

2009

Clustering or overexpression of the transmembrane form of the extracellular matrix proteoglycan agrin in neurons results in the formation of numerous highly motile filopodia-like processes extending from axons and dendrites. Here we show that similar processes can be induced by overexpression of transmembrane-agrin in several non-neuronal cell lines. Mapping of the process-inducing activity in neurons and non-neuronal cells demonstrates that the cytoplasmic part of transmembrane agrin is dispensable and that the extracellular region is necessary for process formation. Site-directed mutagenesis reveals an essential role for the loop between beta-sheets 3 and 4 within the Kazal subdomain of t…

Central Nervous SystemFollistatinanimal structuresBiologyCytoplasmic partPC12 CellsBiochemistryProtein Structure SecondaryNeuromuscular junctionCell membraneExtracellular matrixMolecular Basis of Cell and Developmental BiologyProtein structureChlorocebus aethiopsmedicineAnimalsHumansAgrinMolecular BiologyNeuronsAgrinCell MembraneCell BiologyTransmembrane proteinProtein Structure TertiaryRatsCell biologymedicine.anatomical_structurenervous systemProteoglycanBiochemistryCOS CellsMutagenesis Site-Directedbiology.proteinFemaleChickenshormones hormone substitutes and hormone antagonistsJournal of Biological Chemistry
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Clustering transmembrane-agrin induces filopodia-like processes on axons and dendrites

2005

The transmembrane form of agrin (TM-agrin) is primarily expressed in the CNS, particularly on neurites. To analyze its function, we clustered TM-agrin on neurons using anti-agrin antibodies. On axons from the chick CNS and PNS as well as on axons and dendrites from mouse hippocampal neurons anti-agrin antibodies induced the dose- and time-dependent formation of numerous filopodia-like processes. The processes appeared within minutes after antibody addition and contained a complex cytoskeleton. Formation of processes required calcium, could be inhibited by cytochalasine D, but was not influenced by staurosporine, heparin or pervanadate. Time-lapse video microscopy revealed that the processes…

animal structuresDendritic spineTime FactorsNeuriteCytochalasin BGrowth ConesVideo microscopyChick EmbryoBiologyNervous SystemAntibodiesCellular and Molecular NeuroscienceMicemedicineNeuritesAnimalsAgrinPseudopodiaGrowth coneCytoskeletonMolecular BiologyCells CulturedCytoskeletonAgrinMicroscopy VideoDose-Response Relationship DrugCell MembraneCell DifferentiationCell BiologyDendritesCell biologymedicine.anatomical_structurenervous systemAnimals NewbornNeuronFilopodia
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