Heterotrimeric G protein signaling functions with dynein to promote spindle positioning in C. elegans

J Cell Biol. 2007 Oct 8;179(1):15-22. doi: 10.1083/jcb.200707085. Epub 2007 Oct 1.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans / ultrastructure
  • Caenorhabditis elegans Proteins / antagonists & inhibitors
  • Caenorhabditis elegans Proteins / metabolism
  • Caenorhabditis elegans Proteins / physiology*
  • Dyneins / antagonists & inhibitors
  • Dyneins / metabolism*
  • Dyneins / physiology
  • Embryo, Nonmammalian / metabolism
  • Embryo, Nonmammalian / ultrastructure
  • Green Fluorescent Proteins / analysis
  • Heterotrimeric GTP-Binding Proteins / metabolism
  • Heterotrimeric GTP-Binding Proteins / physiology*
  • Models, Biological
  • RNA Interference
  • Recombinant Fusion Proteins / analysis
  • Signal Transduction*
  • Spindle Apparatus / metabolism*
  • Spindle Apparatus / ultrastructure

Substances

  • Caenorhabditis elegans Proteins
  • G protein regulator 1, C elegans
  • G protein regulator 2, C elegans
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Dyneins
  • Dyrb-1 protein, C elegans
  • Heterotrimeric GTP-Binding Proteins