The precise assembly of a functional nervous system relies on axon guidance cues. Beyond engaging their cognate receptors and initiating signaling cascades that modulate cytoskeletal dynamics, guidance cues also bind components of the extracellular matrix, notably proteoglycans, yet the role and mechanisms of these interactions remain poorly understood. We found that Drosophila secreted semaphorins bind specifically to glycosaminoglycan (GAG) chains of proteoglycans, showing a preference based on the degree of sulfation. Structural analysis of Sema2b unveiled multiple GAG-binding sites positioned outside canonical plexin-binding site, with the highest affinity binding site located at the C-terminal tail, characterized by a lysine-rich helical arrangement that appears to be conserved across secreted semaphorins. In vivo studies revealed a crucial role of the Sema2b C-terminal tail in specifying the trajectory of olfactory receptor neurons. We propose that secreted semaphorins tether to the cell surface through interactions with GAG chains of proteoglycans, facilitating their presentation to cognate receptors on passing axons.

• Klíčová slova
• Sema2b, axon guidance, glycosaminoglycans, semaphorin, semaphorin bridge model,
• MeSH
• axony metabolismus   MeSH
• čichové buňky metabolismus   MeSH
• Drosophila melanogaster metabolismus   MeSH
• glykosaminoglykany metabolismus   MeSH
• navádění axonů * MeSH
• proteiny Drosophily * metabolismus   genetika   MeSH
• proteoglykany * metabolismus   MeSH
• semaforiny * metabolismus   genetika   MeSH
• signální transdukce * MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glykosaminoglykany MeSH
• proteiny Drosophily * MeSH
• proteoglykany * MeSH
• semaforiny * MeSH

Perineuronal nets (PNNs) enwrap mature neurons, playing a role in the control of plasticity and synapse dynamics. PNNs have been shown to have effects on memory formation, retention and extinction in a variety of animal models. It has been proposed that the cavities in PNNs, which contain synapses, can act as a memory store and that they remain stable after events that cause synaptic withdrawal such as anoxia or hibernation. We examine this idea by monitoring place memory before and after synaptic withdrawal caused by acute hibernation-like state (HLS). Animals lacking hippocampal PNNs due to enzymatic digestion by chondroitinase ABC or knockout of the PNN component aggrecan were compared with wild type controls. HLS-induced synapse withdrawal caused a memory deficit, but not to the level of untreated naïve animals and not worsened by PNN attenuation. After HLS, only animals lacking PNNs showed memory restoration or relearning. Absence of PNNs affected the restoration of excitatory synapses on PNN-bearing neurons. The results support a role for hippocampal PNNs in learning, but not in long-term memory storage for correction of deficits.

• MeSH
• extracelulární matrix - proteiny MeSH
• extracelulární matrix * MeSH
• neurony fyziologie   MeSH
• synapse * MeSH
• učení MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• extracelulární matrix - proteiny MeSH