title: Clustering transmembrane-agrin induces filopodia-like processes on axons and dendrites.
abstract: 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 were dynamic and extended laterally along the entire length of the neuron. The lateral processes had growth cones at their tips that initially adhered to the substrate, but subsequently collapsed and were retracted. These data provide the first evidence for a specific role of TM-agrin in shaping the cytoskeleton of neurites in the developing nervous system.
authors.affiliation: Department of Physiological Chemistry, University of Mainz, Duesbergweg 6, D-55099 Mainz, Germany.
authors.forename: Maik
authors.initials: M
authors.lastname: Annies
authors.forename: Godela
authors.initials: G
authors.lastname: Bittcher
authors.forename: Rene
authors.initials: R
authors.lastname: Ramseger
authors.forename: Jürgen
authors.initials: J
authors.lastname: Löschinger
authors.forename: Stefan
authors.initials: S
authors.lastname: Wöll
authors.forename: Elmar
authors.initials: E
authors.lastname: Porten
authors.forename: Christian
authors.initials: C
authors.lastname: Abraham
authors.forename: Markus A
authors.initials: MA
authors.lastname: Rüegg
authors.forename: Stephan
authors.initials: S
authors.lastname: Kröger
mesh_terms: D018171:Agrin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002478:Cells, Cultured; D002642:Chick Embryo; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D020439:Growth Cones / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D018715:Microscopy, Video; D009420:Nervous System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D016501:Neurites / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D011554:Pseudopodia / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D013997:Time Factors
chemical_list: D018171:Agrin; D000906:Antibodies; D003571:Cytochalasin B