Heterotrimeric G proteins direct two modes of asymmetric cell division in the Drosophila nervous system.
In Drosophila, distinct mechanisms orient asymmetric cell division along the apical-basal axis in neuroblasts and along the anterior-posterior axis in sensory organ precursor (SOP) cells. Here, we show that heterotrimeric G proteins are essential for asymmetric cell division in both cell types. The G protein subunit G(alpha)i localizes apically in neuroblasts and anteriorly in SOP cells before and during mitosis. Interfering with G protein function by G(alpha)i overexpression or depletion of heterotrimeric G protein complexes causes defects in spindle orientation and asymmetric localization of determinants. G(alpha)i is colocalized and associated with Pins, a protein that induces the release of the betagamma subunit and might act as a receptor-independent G protein activator. Thus, asymmetric activation of heterotrimeric G proteins by a receptor-independent mechanism may orient asymmetric cell divisions in different cell types.
Schaefer
M
M
Research Institute of Molecular Pathology (I.M.P.), Dr. Bohr Gasse 7, 1030 Vienna, Austria.
Petronczki
M
M
Dorner
D
D
Forte
M
M
Knoblich
J A
JA
D000818:Animals; D030801:Animals, Genetically Modified; D018797:Cell Cycle Proteins; D002455:Cell Division; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins; D019204:GTP-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism; D019476:Insect Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008938:Mitosis; D008954:Models, Biological; D009154:Mutation; D009420:Nervous System / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D009479:Neuropeptides; D011485:Protein Binding; D019076:Transgenes
D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D009479:Neuropeptides; C405164:Pins protein, Drosophila; C098678:insc protein, Drosophila; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins