Binding site for Robo receptors revealed by dissection of the leucine-rich repeat region of Slit

EMBO J. 2004 Nov 10;23(22):4406-12. doi: 10.1038/sj.emboj.7600446. Epub 2004 Oct 21.


Recognition of the large secreted protein Slit by receptors of the Robo family provides fundamental signals in axon guidance and other developmental processes. In Drosophila, Slit-Robo signalling regulates midline crossing and the lateral position of longitudinal axon tracts. We report the functional dissection of Drosophila Slit, using structure analysis, site-directed mutagenesis and in vitro assays. The N-terminal region of Slit consists of a tandem array of four independently folded leucine-rich repeat (LRR) domains, connected by disulphide-tethered linkers. All three Drosophila Robos were found to compete for a single highly conserved site on the concave face of the second LRR domain of Slit. We also found that this domain is sufficient for biological activity in a chemotaxis assay. Other Slit activities may require Slit dimerisation mediated by the fourth LRR domain. Our results show that a small portion of Slit is able to induce Robo signalling and indicate that the distinct functions of Drosophila Robos are encoded in their divergent cytosolic domains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Axons / physiology
  • Binding Sites
  • Cell Line
  • Cell Movement
  • Cells, Cultured
  • Chromatography, Gel
  • Conserved Sequence
  • Crystallography, X-Ray
  • Culture Media, Conditioned
  • Cysteine / chemistry
  • Drosophila / chemistry
  • Drosophila / genetics
  • Drosophila / metabolism
  • Drosophila Proteins / chemistry*
  • Drosophila Proteins / isolation & purification
  • Drosophila Proteins / metabolism
  • Endothelium, Vascular / cytology
  • Humans
  • Leucine / chemistry*
  • Leucine / genetics
  • Leucine / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Nerve Tissue Proteins / chemistry*
  • Nerve Tissue Proteins / isolation & purification
  • Nerve Tissue Proteins / metabolism
  • Protein Binding
  • Protein Structure, Tertiary
  • Receptors, Immunologic / isolation & purification
  • Receptors, Immunologic / metabolism*
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Repetitive Sequences, Amino Acid
  • Sequence Homology, Amino Acid
  • Umbilical Veins / cytology
  • Water / chemistry


  • Culture Media, Conditioned
  • Drosophila Proteins
  • Nerve Tissue Proteins
  • Receptors, Immunologic
  • Recombinant Fusion Proteins
  • roundabout protein
  • sli protein, Drosophila
  • Water
  • Leucine
  • Cysteine