Structure and functional relevance of the Slit2 homodimerization domain.
Slit proteins are secreted ligands that interact with the Roundabout (Robo) receptors to provide important guidance cues in neuronal and vascular development. Slit-Robo signalling is mediated by an interaction between the second Slit domain and the first Robo domain, as well as being dependent on heparan sulphate. In an effort to understand the role of the other Slit domains in signalling, we determined the crystal structure of the fourth Slit2 domain (D4) and examined the effects of various Slit2 constructs on chick retinal ganglion cell axons. Slit2 D4 forms a homodimer using the conserved residues on its concave face, and can also bind to heparan sulphate. We observed that Slit2 D4 frequently results in growth cones with collapsed lamellipodia and that this effect can be inhibited by exogenously added heparan sulphate. Our results show that Slit2 D4-heparan sulphate binding contributes to a Slit-Robo signalling mechanism more intricate than previously thought.
Seiradake
Elena
E
European Molecular Biology Laboratory, Grenoble Outstation, Grenoble, France.
von Philipsborn
Anne C
AC
Henry
Maud
M
Fritz
Martin
M
Lortat-Jacob
Hugues
H
Jamin
Marc
M
Hemrika
Wieger
W
Bastmeyer
Martin
M
Cusack
Stephen
S
McCarthy
Andrew A
AA
D017124:Conserved Sequence; D058575:Decorin; D016326:Extracellular Matrix Proteins / Q000737:chemistry; D006497:Heparan Sulfate / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism*; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D013329:Structure-Activity Relationship; D000098552:Slit Homolog 2 Protein
D058575:Decorin; D016326:Extracellular Matrix Proteins; D006497:Heparan Sulfate; D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D011509:Proteoglycans; D000098552:Slit Homolog 2 Protein; C546878:DCN protein, human