Drosophila Rho-kinase (DRok) is required for tissue morphogenesis in diverse compartments of the egg chamber during oogenesis.
The Rho-kinases are widely utilized downstream targets of the activated Rho GTPase that have been directly implicated in many aspects of Rho-dependent effects on F-actin assembly, acto-myosin contractility, and microtubule stability, and consequently play an essential role in regulating cell shape, migration, polarity, and division. We have determined that the single closely related Drosophila Rho-kinase ortholog, DRok, is required for several aspects of oogenesis, including maintaining the integrity of the oocyte cortex, actin-mediated tethering of nurse cell nuclei, "dumping" of nurse cell contents into the oocyte, establishment of oocyte polarity, and the trafficking of oocyte yolk granules. These defects are associated with abnormalities in DRok-dependent actin dynamics and appear to be mediated by multiple downstream effectors of activated DRok that have previously been implicated in oogenesis. DRok regulates at least one of these targets, the membrane cytoskeletal cross-linker DMoesin, via a direct phosphorylation that is required to promote localization of DMoesin to the oocyte cortex. The collective oogenesis defects associated with DRok deficiency reveal its essential role in multiple aspects of proper oocyte formation and suggest that DRok defines a novel class of oogenesis determinants that function as key regulators of several distinct actin-dependent processes required for proper tissue morphogenesis.
Verdier
Valerie
V
Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA.
Johndrow
James E
JE
Betson
Martha
M
Chen
Guang-Chao
GC
Hughes
David A
DA
Parkhurst
Susan M
SM
Settleman
Jeffrey
J
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D004331:Drosophila melanogaster; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism / Q000502:physiology*; D008840:Microfilament Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D009866:Oogenesis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D054460:rho-Associated Kinases
D000199:Actins; D047908:Intracellular Signaling Peptides and Proteins; D008840:Microfilament Proteins; C071058:moesin; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases