title: A Sensitized Screen for Genes Promoting Invadopodia Function In Vivo: CDC-42 and Rab GDI-1 Direct Distinct Aspects of Invadopodia Formation.
abstract: Invadopodia are specialized membrane protrusions composed of F-actin, actin regulators, signaling proteins, and a dynamically trafficked invadopodial membrane that drive cell invasion through basement membrane (BM) barriers in development and cancer. Due to the challenges of studying invasion in vivo, mechanisms controlling invadopodia formation in their native environments remain poorly understood. We performed a sensitized genome-wide RNAi screen and identified 13 potential regulators of invadopodia during anchor cell (AC) invasion into the vulval epithelium in C. elegans. Confirming the specificity of this screen, we identified the Rho GTPase cdc-42, which mediates invadopodia formation in many cancer cell lines. Using live-cell imaging, we show that CDC-42 localizes to the AC-BM interface and is activated by an unidentified vulval signal(s) that induces invasion. CDC-42 is required for the invasive membrane localization of WSP-1 (N-WASP), a CDC-42 effector that promotes polymerization of F-actin. Loss of CDC-42 or WSP-1 resulted in fewer invadopodia and delayed BM breaching. We also characterized a novel invadopodia regulator, gdi-1 (Rab GDP dissociation inhibitor), which mediates membrane trafficking. We show that GDI-1 functions in the AC to promote invadopodia formation. In the absence of GDI-1, the specialized invadopodial membrane was no longer trafficked normally to the invasive membrane, and instead was distributed to plasma membrane throughout the cell. Surprisingly, the pro-invasive signal(s) from the vulval cells also controls GDI-1 activity and invadopodial membrane trafficking. These studies represent the first in vivo screen for genes regulating invadopodia and demonstrate that invadopodia formation requires the integration of distinct cellular processes that are coordinated by an extracellular cue.
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: Lauren L
authors.initials: LL
authors.lastname: Lohmer
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Clay
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: Kaleb M
authors.initials: KM
authors.lastname: Naegeli
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: Qiuyi
authors.initials: Q
authors.lastname: Chi
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: Joshua W
authors.initials: JW
authors.lastname: Ziel
authors.affiliation: Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Elliott J
authors.initials: EJ
authors.lastname: Hagedorn
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: Jieun E
authors.initials: JE
authors.lastname: Park
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: Ranjay
authors.initials: R
authors.lastname: Jayadev
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: David R
authors.initials: DR
authors.lastname: Sherwood
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000254:growth & development; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development; D029742:Caenorhabditis elegans Proteins / Q000096:biosynthesis / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics*; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000235:genetics; D019204:GTP-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D009369:Neoplasms / Q000235:genetics* / Q000473:pathology; D000069261:Podosomes / Q000235:genetics* / Q000473:pathology; D015398:Signal Transduction
chemical_list: D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; C086796:GDP dissociation inhibitor 1; D020730:Guanine Nucleotide Dissociation Inhibitors; C081779:cdc-42 protein, C elegans; D019204:GTP-Binding Proteins