Going for the Correct Orientation

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Science  12 May 2006:
Vol. 312, Issue 5775, pp. 817
DOI: 10.1126/science.312.5775.817c

Development of the Drosophila sensory organ depends on the polarization and subsequent asymmetric division of sensory organ precursor cells (SOPs), which give rise to the cell types that make up the mature structure. Although SOPs can become polarized and divide asymmetrically in the absence of external signals, achieving the correct orientation depends on extracellular signals transduced through the Frizzled (Fz) receptor. Fz is known to signal through heterotrimeric GTP-binding proteins containing Go-type α subunits, and Katanaev and Tomlinson demonstrate that cells containing mutant Go or overexpressing wild-type Go show defects in both orientation and asymmetric division as well as in the localization of Numb, a protein whose polarized distribution in SOPs is key to cell fate determination. 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 specifying orientation, and the authors propose that it may act to integrate the two. — EMA

Proc. Natl. Acad. Sci. U.S.A. 103, 6524 (2006).

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