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Chataigner LMP, Thärichen L, Beugelink JW, Granneman JCM, Mokiem NJ, Snijder J, Förster F, Janssen BJC. Contactin 2 homophilic adhesion structure and conformational plasticity. Structure 2024; 32:60-73.e5. [PMID: 37992710 DOI: 10.1016/j.str.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/27/2023] [Accepted: 10/26/2023] [Indexed: 11/24/2023]
Abstract
The cell-surface attached glycoprotein contactin 2 is ubiquitously expressed in the nervous system and mediates homotypic cell-cell interactions to organize cell guidance, differentiation, and adhesion. Contactin 2 consists of six Ig and four fibronectin type III domains (FnIII) of which the first four Ig domains form a horseshoe structure important for homodimerization and oligomerization. Here we report the crystal structure of the six-domain contactin 2Ig1-6 and show that the Ig5-Ig6 combination is oriented away from the horseshoe with flexion in interdomain connections. Two distinct dimer states, through Ig1-Ig2 and Ig3-Ig6 interactions, together allow formation of larger oligomers. Combined size exclusion chromatography with multiangle light scattering (SEC-MALS), small-angle X-ray scattering (SAXS) and native MS analysis indicates contactin 2Ig1-6 oligomerizes in a glycan dependent manner. SAXS and negative-stain electron microscopy reveals inherent plasticity of the contactin 2 full-ectodomain. The combination of intermolecular binding sites and ectodomain plasticity explains how contactin 2 can function as a homotypic adhesion molecule in diverse intercellular environments.
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Affiliation(s)
- Lucas M P Chataigner
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Lena Thärichen
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - J Wouter Beugelink
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Joke C M Granneman
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Nadia J Mokiem
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Joost Snijder
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Bert J C Janssen
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands.
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Spead O, Moreland T, Weaver CJ, Costa ID, Hegarty B, Kramer KL, Poulain FE. Teneurin trans-axonal signaling prunes topographically missorted axons. Cell Rep 2023; 42:112192. [PMID: 36857189 PMCID: PMC10131173 DOI: 10.1016/j.celrep.2023.112192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 01/04/2023] [Accepted: 02/14/2023] [Indexed: 03/02/2023] Open
Abstract
Building precise neural circuits necessitates the elimination of axonal projections that have inaccurately formed during development. Although axonal pruning is a selective process, how it is initiated and controlled in vivo remains unclear. Here, we show that trans-axonal signaling mediated by the cell surface molecules Glypican-3, Teneurin-3, and Latrophilin-3 prunes misrouted retinal axons in the visual system. Retinotopic neuron transplantations revealed that pioneer ventral axons that elongate first along the optic tract instruct the pruning of dorsal axons that missort in that region. Glypican-3 and Teneurin-3 are both selectively expressed by ventral retinal ganglion cells and cooperate for correcting missorted dorsal axons. The adhesion G-protein-coupled receptor Latrophilin-3 signals along dorsal axons to initiate the elimination of topographic sorting errors. Altogether, our findings show an essential function for Glypican-3, Teneurin-3, and Latrophilin-3 in topographic tract organization and demonstrate that axonal pruning can be initiated by signaling among axons themselves.
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Affiliation(s)
- Olivia Spead
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Trevor Moreland
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Cory J Weaver
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Irene Dalla Costa
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Brianna Hegarty
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | | | - Fabienne E Poulain
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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Dumoulin A, Stoeckli ET. Looking for Guidance - Models and Methods to Study Axonal Navigation. Neuroscience 2023; 508:30-39. [PMID: 35940454 DOI: 10.1016/j.neuroscience.2022.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 01/17/2023]
Abstract
The molecular mechanisms of neural circuit formation have been of interest to Santiago Ramón y Cajal and thousands of neuroscientists sharing his passion for neural circuits ever since. Cajal was a brilliant observer and taught us about the connections and the morphology of neurons in the adult and developing nervous system. Clearly, we will not learn about molecular mechanisms by just looking at brain sections or cells in culture. Technically, we had to come a long way to today's possibilities that allow us to perturb target gene expression and watch the consequences of our manipulations on navigating axons in situ. In this review, we summarize landmark steps towards modern live-imaging approaches used to study the molecular basis of axon guidance.
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Affiliation(s)
- Alexandre Dumoulin
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Esther T Stoeckli
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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Beckers A, Masin L, Dyck A, Bergmans S, Vanhunsel S, Zhang A, Verreet T, Poulain F, Farrow K, Moons L. Optic nerve injury-induced regeneration in the adult zebrafish is accompanied by spatiotemporal changes in mitochondrial dynamics. Neural Regen Res 2023; 18:219-225. [PMID: 35799546 PMCID: PMC9241429 DOI: 10.4103/1673-5374.344837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Axonal regeneration in the central nervous system is an energy-intensive process. In contrast to mammals, adult zebrafish can functionally recover from neuronal injury. This raises the question of how zebrafish can cope with this high energy demand. We previously showed that in adult zebrafish, subjected to an optic nerve crush, an antagonistic axon-dendrite interplay exists wherein the retraction of retinal ganglion cell dendrites is a prerequisite for effective axonal repair. We postulate a ‘dendrites for regeneration’ paradigm that might be linked to intraneuronal mitochondrial reshuffling, as ganglion cells likely have insufficient resources to maintain dendrites and restore axons simultaneously. Here, we characterized both mitochondrial distribution and mitochondrial dynamics within the different ganglion cell compartments (dendrites, somas, and axons) during the regenerative process. Optic nerve crush resulted in a reduction of mitochondria in the dendrites during dendritic retraction, whereafter enlarged mitochondria appeared in the optic nerve/tract during axonal regrowth. Upon dendritic regrowth in the retina, mitochondrial density inside the retinal dendrites returned to baseline levels. Moreover, a transient increase in mitochondrial fission and biogenesis was observed in retinal ganglion cell somas after optic nerve damage. Taken together, these findings suggest that during optic nerve injury-induced regeneration, mitochondria shift from the dendrites to the axons and back again and that temporary changes in mitochondrial dynamics support axonal and dendritic regrowth after optic nerve crush.
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Moreland T, Poulain FE. To Stick or Not to Stick: The Multiple Roles of Cell Adhesion Molecules in Neural Circuit Assembly. Front Neurosci 2022; 16:889155. [PMID: 35573298 PMCID: PMC9096351 DOI: 10.3389/fnins.2022.889155] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 03/28/2022] [Indexed: 01/02/2023] Open
Abstract
Precise wiring of neural circuits is essential for brain connectivity and function. During development, axons respond to diverse cues present in the extracellular matrix or at the surface of other cells to navigate to specific targets, where they establish precise connections with post-synaptic partners. Cell adhesion molecules (CAMs) represent a large group of structurally diverse proteins well known to mediate adhesion for neural circuit assembly. Through their adhesive properties, CAMs act as major regulators of axon navigation, fasciculation, and synapse formation. While the adhesive functions of CAMs have been known for decades, more recent studies have unraveled essential, non-adhesive functions as well. CAMs notably act as guidance cues and modulate guidance signaling pathways for axon pathfinding, initiate contact-mediated repulsion for spatial organization of axonal arbors, and refine neuronal projections during circuit maturation. In this review, we summarize the classical adhesive functions of CAMs in axonal development and further discuss the increasing number of other non-adhesive functions CAMs play in neural circuit assembly.
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