Ruan, W., Long, H., Vuong, D.H., Rao, Y. (2002). Bifocal is a downstream target of the Ste20-like serine/threonine kinase Misshapen in regulating photoreceptor growth cone targeting in Drosophila.  Neuron 36(5): 831--842.

FBrf0156013

Research paper

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.