title: Distinct rac activation pathways control Caenorhabditis elegans cell migration and axon outgrowth.
abstract: Rac GTPases act as molecular switch in various morphogenic events. However, the regulation of their activities during the development of multicellular organisms is not well understood. Caenorhabditis elegans rac genes ced-10 and mig-2 have been shown to act redundantly to control P cell migration and the axon outgrowth of D type motoneurons. We showed that ced-10 and mig-2 also control amphid axon outgrowth and amphid dendrite fasciculation in a redundant fashion. Our biochemical and genetic data indicate that unc-73, which encodes a protein related to Trio-like guanine nucleotide exchange factor, acts as a direct activator of ced-10 and mig-2 during P cell migration and axon outgrowth of D type motoneurons and amphid sensory neurons. Furthermore, rac regulators ced-2/crkII and ced-5/dock180 function genetically upstream of ced-10 and mig-2 during axon outgrowth of D type motoneurons and act upstream of mig-2 but not ced-10 during P cell migration. However, neither ced-2/crkII nor ced-5/dock180 is involved in amphid axon outgrowth. Therefore, distinct rac regulators control ced-10 and mig-2 differentially in various cellular processes.
authors.affiliation: Department of Zoology, National Taiwan University, No1 Sec4 Roosevelt Road, Taipei 10617, Taiwan. yichun@ccms.ntu.edu.tw
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Wu
authors.forename: Ting-Wen
authors.initials: TW
authors.lastname: Cheng
authors.forename: Ming-Chia
authors.initials: MC
authors.lastname: Lee
authors.forename: Nei-Ying
authors.initials: NY
authors.lastname: Weng
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins; D001369:Axons / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009475:Neurons, Afferent / Q000166:cytology / Q000502:physiology*; D015398:Signal Transduction; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; C407268:CED-10 protein, C elegans; C438369:CED-12 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D020662:Guanine Nucleotide Exchange Factors; D009419:Nerve Tissue Proteins; C111263:UNC-73 protein, C elegans; D020744:rac GTP-Binding Proteins