title: Three C. elegans Rac proteins and several alternative Rac regulators control axon guidance, cell migration and apoptotic cell phagocytosis.
abstract: The Caenorhabditis elegans genome contains three rac-like genes, ced-10, mig-2, and rac-2. We report that ced-10, mig-2 and rac-2 act redundantly in axon pathfinding: inactivating one gene had little effect, but inactivating two or more genes perturbed both axon outgrowth and guidance. mig-2 and ced-10 also have redundant functions in some cell migrations. By contrast, ced-10 is uniquely required for cell-corpse phagocytosis, and mig-2 and rac-2 have only subtle roles in this process. Rac activators are also used differentially. The UNC-73 Trio Rac GTP exchange factor affected all Rac pathways in axon pathfinding and cell migration but did not affect cell-corpse phagocytosis. CED-5 DOCK180, which acts with CED-10 Rac in cell-corpse phagocytosis, acted with MIG-2 but not CED-10 in axon pathfinding. Thus, distinct regulatory proteins modulate Rac activation and function in different developmental processes.
authors.affiliation: Department of Molecular Biosciences, University of Kansas, 5049 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA. erikl@ku.edu
authors.forename: E A
authors.initials: EA
authors.lastname: Lundquist
authors.forename: P W
authors.initials: PW
authors.lastname: Reddien
authors.forename: E
authors.initials: E
authors.lastname: Hartwieg
authors.forename: H R
authors.initials: HR
authors.lastname: Horvitz
authors.forename: C I
authors.initials: CI
authors.lastname: Bargmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D001369:Axons / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000196:embryology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002465:Cell Movement; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D005810:Multigene Family; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009420:Nervous System / Q000196:embryology; D010587:Phagocytosis; D017386:Sequence Homology, Amino Acid; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000097766:RAC2 GTP-Binding Protein
chemical_list: D029742:Caenorhabditis elegans Proteins; D019204:GTP-Binding Proteins; D015801:Helminth Proteins; D009419:Nerve Tissue Proteins; D020744:rac GTP-Binding Proteins; D000097766:RAC2 GTP-Binding Protein; C407268:CED-10 protein, C elegans; C111263:UNC-73 protein, C elegans; C442327:Mig-2 protein, C elegans