title: Heterotrimeric G protein signaling functions with dynein to promote spindle positioning in C. elegans.
abstract: Proper orientation and positioning of the mitotic spindle is essential for the correct segregation of fate determinants during asymmetric cell division. Although heterotrimeric G proteins and their regulators are essential for spindle positioning in many cell types, their mechanism of action remains unclear. In this study, we show that dyrb-1, which encodes a dynein light chain, provides a functional link between heterotrimeric G protein signaling and dynein activity during spindle positioning in Caenorhabditis elegans. Embryos depleted of dyrb-1 display phenotypes similar to a weak loss of function of dynein activity, indicating that DYRB-1 is a positive regulator of dynein. We find that the depletion of dyrb-1 enhances the spindle positioning defect of weak loss of function alleles of two regulators of G protein signaling, LIN-5 and GPR-1/2, and that DYRB-1 physically associates with these two proteins. These results indicate that dynein activity functions with regulators of G protein signaling to regulate common downstream effectors during spindle positioning in the early C. elegans embryo.
authors.affiliation: ETH Zurich, Institute of Biochemistry, 8093 Zurich, Switzerland.
authors.forename: Claudia
authors.initials: C
authors.lastname: Couwenbergs
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Labbé
authors.forename: Morgan
authors.initials: M
authors.lastname: Goulding
authors.forename: Thomas
authors.initials: T
authors.lastname: Marty
authors.forename: Bruce
authors.initials: B
authors.lastname: Bowerman
authors.forename: Monica
authors.initials: M
authors.lastname: Gotta
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D004398:Dyneins / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000648:ultrastructure; D049452:Green Fluorescent Proteins / Q000032:analysis; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000032:analysis; D015398:Signal Transduction; D008941:Spindle Apparatus / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D029742:Caenorhabditis elegans Proteins; C475458:G protein regulator 1, C elegans; C475459:G protein regulator 2, C elegans; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D004398:Dyneins; C525402:Dyrb-1 protein, C elegans; D020962:Heterotrimeric GTP-Binding Proteins