biostudies-literatureNagy GNCarlsbergfondetDanmarks GrundforskningsfondMedical Research CouncilNIMH NIH HHSDr Miriam and Sheldon G. Adelson Medical FoundationWellcome TrustNovo Nordisk FondenU.S. Department of Health & Human Services | National Institutes of Health2723https://www.ebi.ac.uk/biostudies/studies/S-EPMC10978931biostudies-literatureUnknown15(1)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 foNature communicationsStructure and function of Semaphorin-5A glycosaminoglycan interactions.PMC10978931203141/Z/16/ZNNF22OC0073736MR/T000503/1223133/Z/21/ZCF20-0412R01 MH119346DNRF107Zhao XFMiller RLEl Omari KDuman RClausen HWagner ANagy GNHarlos KKarlsson RWang KGiger RJJones EYfalseStructure and function of Semaphorin-5A glycosaminoglycan interactions.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 fo2024-01-01T00:00:00Z2024 Mar2026-06-01T21:47:32.399Z2025-04-04T19:12:32.806ZS-EPMC109789313854871510.1038/s41467-024-46725-7