The Rho GTPase-activating proteins RGA-3 and RGA-4 are required to set the initial size of PAR domains in Caenorhabditis elegans one-cell embryos.
Caenorhabditis elegans embryos establish cortical domains of PAR proteins of reproducible size before asymmetric cell division. The ways in which the size of these domains is set remain unknown. Here we identify the GTPase-activating proteins (GAPs) RGA-3 and RGA-4, which regulate the activity of the small GTPase RHO-1. rga-3/4(RNAi) embryos have a hypercontractile cortex, and the initial relative size of their anterior and posterior PAR domains is altered. Thus, RHO-1 activity appears to control the level of cortical contractility and concomitantly the size of cortical domains. These data support the idea that in C. elegans embryos the initial size of the PAR domains is set by regulating the contractile activity of the acto-myosin cytoskeleton through the activity of RHO-1. RGA-3/4 have functions different from CYK-4, the other known GAP required for the first cell division, showing that different GAPs cooperate to control the activity of the acto-myosin cytoskeleton in the first cell division of C. elegans embryos.
Schonegg
Stephanie
S
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany. schonegg@mpi-cbg.de
Constantinescu
Alexandru T
AT
Hoege
Carsten
C
Hyman
Anthony A
AA
D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000201:enzymology / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D016764:Cell Polarity / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D034622:RNA Interference
D029742:Caenorhabditis elegans Proteins; D020690:GTPase-Activating Proteins; C524405:RGA-3 protein, C elegans; C524406:RGA-4 protein, C elegans; C087977:par-2 protein, C elegans; C085379:rho GTPase-activating protein; D000205:Actomyosin; D009218:Myosins