title: CYK-4/GAP provides a localized cue to initiate anteroposterior polarity upon fertilization.
abstract: The Caenorhabditis elegans anteroposterior axis is established in response to fertilization by sperm. Here we present evidence that RhoA, the guanine nucleotide-exchange factor ECT-2, and the Rho guanosine triphosphatase-activating protein CYK-4 modulate myosin light-chain activity to create a gradient of actomyosin, which establishes the anterior domain. CYK-4 is enriched within sperm, and paternally donated CYK-4 is required for polarity. These data suggest that CYK-4 provides a molecular link between fertilization and polarity establishment in the one-cell embryo. Orthologs of CYK-4 are expressed in sperm of other species, which suggests that this cue may be evolutionarily conserved.
authors.affiliation: Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Noah
authors.initials: N
authors.lastname: Jenkins
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Saam
authors.forename: Susan E
authors.initials: SE
authors.lastname: Mango
mesh_terms: D000205:Actomyosin / Q000502:physiology; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D016764:Cell Polarity; D048749:Cytokinesis; D003599:Cytoskeleton / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000737:chemistry / Q000166:cytology* / Q000502:physiology; D005260:Female; D005306:Fertilization; D020690:GTPase-Activating Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D020662:Guanine Nucleotide Exchange Factors / Q000032:analysis / Q000235:genetics / Q000502:physiology; D008297:Male; D018994:Myosin Light Chains / Q000378:metabolism; D024462:Myosin Type II / Q000032:analysis; D015388:Organelles / Q000737:chemistry; D011506:Proteins / Q000032:analysis; D034622:RNA Interference; D013094:Spermatozoa / Q000737:chemistry / Q000648:ultrastructure; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000502:physiology
chemical_list: C513388:CYK-4 protein, C elegans; D029742:Caenorhabditis elegans Proteins; C507872:Ect-2 protein, C elegans; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D018994:Myosin Light Chains; D011506:Proteins; C512642:par-6 protein, C elegans; D000205:Actomyosin; D024462:Myosin Type II; D020742:rhoA GTP-Binding Protein