title: Differential roles of α-, β-, and γ-actin in axon growth and collateral branch formation in motoneurons.
abstract: Axonal branching and terminal arborization are fundamental events during the establishment of synaptic connectivity. They are triggered by assembly of actin filaments along axon shafts giving rise to filopodia. The specific contribution of the three actin isoforms, Actα, Actβ, and Actγ, to filopodia stability and dynamics during this process is not well understood. Here, we report that Actα, Actβ, and Actγ isoforms are expressed in primary mouse motoneurons and their transcripts are translocated into axons. shRNA-mediated depletion of Actα reduces axonal filopodia dynamics and disturbs collateral branch formation. Knockdown of Actβ reduces dynamic movements of growth cone filopodia and impairs presynaptic differentiation. Ablation of Actβ or Actγ leads to compensatory up-regulation of the two other isoforms, which allows maintenance of total actin levels and preserves F-actin polymerization. Collectively, our data provide evidence for specific roles of different actin isoforms in spatial regulation of actin dynamics and stability in axons of developing motoneurons.
authors.affiliation: Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany.
authors.forename: Mehri
authors.initials: M
authors.lastname: Moradi
authors.affiliation: Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany.
authors.forename: Rajeeve
authors.initials: R
authors.lastname: Sivadasan
authors.affiliation: Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Saal
authors.affiliation: Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Lüningschrör
authors.affiliation: Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Dombert
authors.affiliation: Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany.
authors.forename: Reena Jagdish
authors.initials: RJ
authors.lastname: Rathod
authors.affiliation: Institute for Pharmacology and Toxicology, Medical Faculty, University of Magdeburg, 39120 Magdeburg, Germany.|Center for Behavioral Brain Sciences, Medical Faculty, University of Magdeburg, 39120 Magdeburg, Germany.
authors.forename: Daniela C
authors.initials: DC
authors.lastname: Dieterich
authors.affiliation: Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Blum
authors.affiliation: Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany sendtner_m@ukw.de.
authors.forename: Michael
authors.identifier: 0000-0002-4737-2974
authors.initials: M
authors.lastname: Sendtner
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000818:Animals; D001369:Axons / Q000378:metabolism*; D002478:Cells, Cultured; D020439:Growth Cones / Q000378:metabolism; D051379:Mice; D009046:Motor Neurons / Q000378:metabolism*; D020932:Nerve Growth Factor / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology; D011554:Pseudopodia / Q000378:metabolism; D011984:Sensory Receptor Cells; D015854:Up-Regulation / Q000502:physiology
chemical_list: D000199:Actins; D020932:Nerve Growth Factor