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 2 Ig1-6 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 2 Ig1-6 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.
| Original language | English |
|---|---|
| Pages (from-to) | 60-73.e5 |
| Journal | Structure |
| Volume | 32 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 4 Jan 2024 |
Bibliographical note
Publisher Copyright:© 2023 Elsevier Ltd
Funding
We thank the staff of the DLS beamline I03 for help with X-ray diffraction data collection and DLS beamline B21 for help with SAXS data collection. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme with grant agreement No. 677500 (to B.J.C.J.). We thank the staff of the DLS beamline I03 for help with X-ray diffraction data collection and DLS beamline B21 for help with SAXS data collection. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme with grant agreement No. 677500 (to B.J.C.J.). B.J.C.J conceived the project. L.M.P.C designed experiments with input from B.J.C.J. B.J.C.J and J.C.M.G cloned constructs. L.M.P.C purified recombinant proteins and performed structural and biophysical experiments (X-ray diffraction and SAXS). J.W.B purified mutant proteins and performed SEC-MALS experiments. L.M.P.C processed various data (SEC-MALS, X-ray diffraction, and SAXS) L.T performed negative stain electron microscopy experiments and data analysis under supervision of F.F. N.J.M performed native mass spectrometry experiments and data analysis under supervision of J.S. L.M.P.C analyzed the structural information. B.J.C.J supervised the project. L.M.P.C and B.J.C.J and wrote the manuscript. All authors commented on the manuscript. The authors declare no competing interests.
| Funders | Funder number |
|---|---|
| Horizon 2020 Framework Programme | |
| European Research Council | |
| Horizon 2020 | 677500 |
Keywords
- Binding Sites
- Cell Adhesion Molecules, Neuronal/chemistry
- Cell Adhesion/physiology
- Contactin 2
- Molecular Conformation
- Scattering, Small Angle
- X-Ray Diffraction