Sci. STKE, 2 May 2006
DEVELOPMENT Going for the Correct Orientation
Development of the Drosophila sensory organ depends on the polarization and subsequent asymmetric division of sensory organ precursor cells (SOPs), which give rise to all of the cell types that make up the mature structure. Although SOPs can become polarized and divide asymmetrically in the absence of external signals, their ability to achieve the correct orientation depends on extracellular signals transduced through the Frizzled (Fz) receptor. Fz is known to signal through heterotrimeric guanosine triphosphate (GTP)-binding proteins containing Go-type α subunits in some Drosophila systems, leading Katanaev and Tomlinson to investigate its role in sensory organ development. Clonal cells containing mutant Go or overexpressing wild-type or activated Go showed phenotypic defects in both orientation and asymmetric division, as well as mislocalization of Numb, a phosphoprotein whose polarized distribution in SOPs is key to cell fate determination. Go itself was asymmetrically distributed in mitotic SOPs and both coprecipitated with Pins (Partner of Inscuteable, a protein that binds to Gα and is part of a complex necessary for asymmetric distribution of Numb) and interacted genetically with it. The phenotypic effects of overexpressing wild-type Go depended on the expression of Fz and were enhanced by Fz overexpression. Go thus appears to be involved both in the establishment of asymmetry and in determining its correct orientation, leading the authors to propose that it may act to integrate these two processes.
Citation: Going for the Correct Orientation. Sci. STKE 2006, tw146 (2006).
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