Bifocal Is a Downstream Target of the Ste20-like serine/threonine Kinase Misshapen in Regulating Photoreceptor Growth Cone Targeting in Drosophila

Neuron. 2002 Dec 5;36(5):831-42. doi: 10.1016/s0896-6273(02)01027-9.


Misshapen (Msn) has been proposed to shut down Drosophila photoreceptor (R cell) growth cone motility in response to targeting signals linked by the SH2/SH3 adaptor protein Dock. Here, we show that Bifocal (Bif), a putative cytoskeletal regulator, is a component of the Msn pathway for regulating R cell growth cone targeting. bif displays strong genetic interaction with msn. Phenotypic analysis indicates a specific role for Bif to terminate R1-R6 growth cones. Biochemical studies show that Msn associates directly with Bif and phosphorylates Bif in vitro. Cell culture studies demonstrate that Msn interacts with Bif to regulate F-actin structure and filopodium formation. We propose that Bif functions downstream of Msn to reorganize actin cytoskeleton in decelerating R cell growth cone motility at the target region.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Movement / physiology
  • Cells, Cultured
  • Cytoskeletal Proteins*
  • Cytoskeleton / metabolism
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / cytology
  • Drosophila melanogaster / embryology
  • Drosophila melanogaster / physiology*
  • Eye Proteins / genetics
  • Eye Proteins / metabolism*
  • Gene Dosage
  • Green Fluorescent Proteins
  • Growth Cones / metabolism*
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Phosphorylation
  • Photoreceptor Cells, Invertebrate / cytology
  • Photoreceptor Cells, Invertebrate / physiology
  • Protein Binding
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Pseudopodia / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction / physiology*


  • Cytoskeletal Proteins
  • Drosophila Proteins
  • Eye Proteins
  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • bif protein, Drosophila
  • Green Fluorescent Proteins
  • msn protein, Drosophila
  • Protein-Serine-Threonine Kinases