Download MendeleyStructure and function of Semaphorin-5A glycosaminoglycan interactions.
Nagy, G.N., Zhao, X.F., Karlsson, R., Wang, K., Duman, R., Harlos, K., El Omari, K., Wagner, A., Clausen, H., Miller, R.L., Giger, R.J., Jones, E.Y.(2024) Nat Commun 15: 2723-2723
- PubMed: 38548715
- DOI: https://doi.org/10.1038/s41467-024-46725-7
- Primary Citation of Related Structures:
8CKG, 8CKK, 8CKL, 8CKM - PubMed Abstract:
Integration of extracellular signals by neurons is pivotal for brain development, plasticity, and repair. Axon guidance relies on receptor-ligand interactions crosstalking with extracellular matrix components. Semaphorin-5A (Sema5A) is a bifunctional guidance cue exerting attractive and inhibitory effects on neuronal growth through the interaction with heparan sulfate (HS) and chondroitin sulfate (CS) glycosaminoglycans (GAGs), respectively. Sema5A harbors seven thrombospondin type-1 repeats (TSR1-7) important for GAG binding, however the underlying molecular basis and functions in vivo remain enigmatic. Here we dissect the structural basis for Sema5A:GAG specificity and demonstrate the functional significance of this interaction in vivo. Using x-ray crystallography, we reveal a dimeric fold variation for TSR4 that accommodates GAG interactions. TSR4 co-crystal structures identify binding residues validated by site-directed mutagenesis. In vitro and cell-based assays uncover specific GAG epitopes necessary for TSR association. We demonstrate that HS-GAG binding is preferred over CS-GAG and mediates Sema5A oligomerization. In vivo, Sema5A:GAG interactions are necessary for Sema5A function and regulate Plexin-A2 dependent dentate progenitor cell migration. Our study rationalizes Sema5A associated developmental and neurological disorders and provides mechanistic insights into how multifaceted guidance functions of a single transmembrane cue are regulated by proteoglycans.
Organizational Affiliation:
Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK. nagy.gergely.nandor@vbk.bme.hu.
