title: Arp2/3 mediates early endosome dynamics necessary for the maintenance of PAR asymmetry in Caenorhabditis elegans.
abstract: The widely conserved Arp2/3 complex regulates branched actin dynamics that are necessary for a variety of cellular processes. In Caenorhabditis elegans, the actin cytoskeleton has been extensively characterized in its role in establishing PAR asymmetry; however, the contributions of actin to the maintenance of polarity before the onset of mitosis are less clear. Endocytic recycling has emerged as a key mechanism in the dynamic stabilization of cellular polarity, and the large GTPase dynamin participates in the stabilization of cortical polarity during maintenance phase via endocytosis in C. elegans. Here we show that disruption of Arp2/3 function affects the formation and localization of short cortical actin filaments and foci, endocytic regulators, and polarity proteins during maintenance phase. We detect actin associated with events similar to early endosomal fission, movement of endosomes into the cytoplasm, and endosomal movement from the cytoplasm to the plasma membrane, suggesting the involvement of actin in regulating processes at the early endosome. We also observe aberrant accumulations of PAR-6 cytoplasmic puncta near the centrosome along with early endosomes. We propose a model in which Arp2/3 affects the efficiency of rapid endocytic recycling of polarity cues that ultimately contributes to their stable maintenance.
authors.affiliation: Department of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Shivas
authors.forename: Ahna R
authors.initials: AR
authors.lastname: Skop
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D051377:Actin-Related Protein 2 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D015536:Down-Regulation; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D055785:Gene Knockdown Techniques; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D011493:Protein Kinase C / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D021381:Protein Transport; D034622:RNA Interference; D059008:Time-Lapse Imaging; D020696:rab5 GTP-Binding Proteins / Q000378:metabolism
chemical_list: D051377:Actin-Related Protein 2; D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; C476568:arx-2 protein, C elegans; C081779:cdc-42 protein, C elegans; C512642:par-6 protein, C elegans; C097238:PAR-3 protein, C elegans; D017346:Protein Serine-Threonine Kinases; C115015:PKC-3 protein; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D020696:rab5 GTP-Binding Proteins; D034281:Dynamins