title: The actin-binding protein UNC-115/abLIM controls formation of lamellipodia and filopodia and neuronal morphogenesis in Caenorhabditis elegans.
abstract: The roles of actin-binding proteins in development and morphogenesis are not well understood. The actin-binding protein UNC-115 has been implicated in cytoskeletal signaling downstream of Rac in Caenorhabditis elegans axon pathfinding, but the cellular role of UNC-115 in this process remains undefined. Here we report that UNC-115 overactivity in C. elegans neurons promotes the formation of neurites and lamellipodial and filopodial extensions similar to those induced by activated Rac and normally found in C. elegans growth cones. We show that UNC-115 activity in neuronal morphogenesis is enhanced by two molecular mechanisms: when ectopically driven to the plasma membrane by the myristoylation sequence of c-Src, and by mutation of a putative serine phosphorylation site in the actin-binding domain of UNC-115. In support of the hypothesis that UNC-115 modulates actin cytoskeletal organization, we show that UNC-115 activity in serum-starved NIH 3T3 fibroblasts results in the formation of lamellipodia and filopodia. We conclude that UNC-115 is a novel regulator of the formation of lamellipodia and filopodia in neurons, possibly in the growth cone during axon pathfinding.
authors.affiliation: Department of Molecular Biosciences, 5049 Haworth Hall, 1200 Sunnyside Avenue, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Yieyie
authors.initials: Y
authors.lastname: Yang
authors.forename: Erik A
authors.initials: EA
authors.lastname: Lundquist
mesh_terms: D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000033:anatomy & histology / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009024:Morphogenesis; D041681:NIH 3T3 Cells; D009474:Neurons / Q000166:cytology / Q000502:physiology; D011554:Pseudopodia / Q000502:physiology* / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology
chemical_list: D000199:Actins; D029742:Caenorhabditis elegans Proteins; D008840:Microfilament Proteins; D011993:Recombinant Fusion Proteins; C472306:UNC-115 protein, C elegans