title: Regulation of cortical contractility and spindle positioning by the protein phosphatase 6 PPH-6 in one-cell stage C. elegans embryos.
abstract: Modulation of the microtubule and the actin cytoskeleton is crucial for proper cell division. Protein phosphorylation is known to be an important regulatory mechanism modulating these cytoskeletal networks. By contrast, there is a relative paucity of information regarding how protein phosphatases contribute to such modulation. Here, we characterize the requirements for protein phosphatase PPH-6 and its associated subunit SAPS-1 in one-cell stage C. elegans embryos. We establish that the complex of PPH-6 and SAPS-1 (PPH-6/SAPS-1) is required for contractility of the actomyosin network and proper spindle positioning. Our analysis demonstrates that PPH-6/SAPS-1 regulates the organization of cortical non-muscle myosin II (NMY-2). Accordingly, we uncover that PPH-6/SAPS-1 contributes to cytokinesis by stimulating actomyosin contractility. Furthermore, we demonstrate that PPH-6/SAPS-1 is required for the proper generation of pulling forces on spindle poles during anaphase. Our results indicate that this requirement is distinct from the role in organizing the cortical actomyosin network. Instead, we uncover that PPH-6/SAPS-1 contributes to the cortical localization of two positive regulators of pulling forces, GPR-1/2 and LIN-5. Our findings provide the first insights into the role of a member of the PP6 family of phosphatases in metazoan development.
authors.affiliation: Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Katayoun
authors.initials: K
authors.lastname: Afshar
authors.forename: Michael E
authors.initials: ME
authors.lastname: Werner
authors.forename: Yu Chung
authors.initials: YC
authors.lastname: Tse
authors.forename: Michael
authors.initials: M
authors.lastname: Glotzer
authors.forename: Pierre
authors.initials: P
authors.lastname: Gönczy
mesh_terms: D000705:Anaphase / Q000235:genetics / Q000502:physiology; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000201:enzymology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D048749:Cytokinesis / Q000235:genetics / Q000502:physiology; D003599:Cytoskeleton / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D018507:Gene Expression Regulation, Developmental; D047468:Immunoprecipitation; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D010749:Phosphoprotein Phosphatases; C106079:protein phosphatase 6