IKK epsilon regulates F actin assembly and interacts with Drosophila IAP1 in cellular morphogenesis

Curr Biol. 2006 Aug 8;16(15):1531-7. doi: 10.1016/j.cub.2006.06.032.


Differentiated cells assume complex shapes through polarized cell migration and growth. These processes require the restricted organization of the actin cytoskeleton at limited subcellular regions. IKK epsilon is a member of the IkappaB kinase family, and its developmental role has not been clear. Drosophila IKK epsilon was localized to the ruffling membrane of cultured cells and was required for F actin turnover at the cell margin. In IKK epsilon mutants, tracheal terminal cells, bristles, and arista laterals, which require accurate F actin assembly for their polarized elongation, all exhibited aberrantly branched morphology. These phenotypes were sensitive to a change in the dosage of Drosophila inhibitor of apoptosis protein 1 (DIAP1) and the caspase DRONC without apparent change in cell viability. In contrast to this, hyperactivation of IKK epsilon destabilized F actin-based structures. Expression of a dominant-negative form of IKK epsilon increased the amount of DIAP1. The results suggest that at the physiological level, IKK epsilon acts as a negative regulator of F actin assembly and maintains the fidelity of polarized elongation during cell morphogenesis. This IKK epsilon function involves the negative regulation of the nonapoptotic activity of DIAP1.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism*
  • Animals
  • Apoptosis / physiology*
  • Blotting, Western
  • Cell Differentiation / physiology*
  • Drosophila / physiology*
  • Drosophila Proteins / metabolism*
  • Genetic Testing
  • Histocytochemistry
  • I-kappa B Kinase / metabolism*
  • Inhibitor of Apoptosis Proteins / metabolism*
  • Microscopy, Fluorescence
  • Morphogenesis / physiology*
  • Trachea / cytology
  • Trachea / growth & development


  • Actins
  • DIAP1 protein, Drosophila
  • Drosophila Proteins
  • Inhibitor of Apoptosis Proteins
  • I-kappa B Kinase