title: Coupling of cortical dynein and G alpha proteins mediates spindle positioning in Caenorhabditis elegans.
abstract: Despite being essential for spatial cell division control, the mechanisms governing spindle positioning remain incompletely understood. In the Caenorhabditis elegans one-cell stage embryo, the spindle becomes asymmetrically positioned during anaphase through the action of as-yet unidentified cortical force generators that pull on astral microtubules and that depend on two G alpha proteins and associated proteins. We performed spindle-severing experiments following temporally restricted gene inactivation and drug exposure, and established that microtubule dynamics and dynein are both required for generating efficient pulling forces. We found that the G alpha-associated proteins GPR-1/2 and LIN-5 interact in vivo with LIS-1, a component of the dynein complex. Moreover, we discovered that the LIN-5, GPR-1/2 and the G alpha proteins promote the presence of the dynein complex at the cell cortex. Our findings suggest a mechanism by which the G alpha proteins enable GPR-1/2 and LIN-5 recruitment to the cortex, thus ensuring the presence of cortical dynein. Together with microtubule dynamics, this allows pulling forces to be exerted and proper cell division to be achieved.
authors.affiliation: Swiss Institute for Experimental Cancer Research (ISREC), Swiss Federal Institute of Technology (EPFL), School of Life Sciences, Lausanne, Switzerland CH-1066.
authors.forename: Tu
authors.initials: T
authors.lastname: Nguyen-Ngoc
authors.forename: Katayoun
authors.initials: K
authors.lastname: Afshar
authors.forename: Pierre
authors.initials: P
authors.lastname: Gönczy
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D016764:Cell Polarity; D004398:Dyneins / Q000378:metabolism*; D044385:GTP-Binding Protein alpha Subunits / Q000378:metabolism*; D008870:Microtubules / Q000502:physiology; D008941:Spindle Apparatus / Q000502:physiology*
chemical_list: D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; D044385:GTP-Binding Protein alpha Subunits; C404808:lin-5 protein, C elegans; D004398:Dyneins