A Proteomic Screen of Neuronal Cell-Surface Molecules Reveals IgLONs as Structurally Conserved Interaction Modules at the Synapse

Fanomezana M. Ranaivoson, Liam S. Turk, Sinem Ozgul, Sumie Kakehi, Sventja von Daake, Nicole Lopez, Laura Trobiani, Antonella De Jaco, Natalia Denissova, Borries Demeler, Engin Özkan, Gaetano T. Montelione, Davide Comoletti

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


In the developing brain, cell-surface proteins play crucial roles, but their protein-protein interaction network remains largely unknown. A proteomic screen identified 200 interactions, 89 of which were not previously published. Among these interactions, we find that the IgLONs, a family of five cell-surface neuronal proteins implicated in various human disorders, interact as homo- and heterodimers. We reveal their interaction patterns and report the dimeric crystal structures of Neurotrimin (NTRI), IgLON5, and the neuronal growth regulator 1 (NEGR1)/IgLON5 complex. We show that IgLONs maintain an extended conformation and that their dimerization occurs through the first Ig domain of each monomer and is Ca2+ independent. Cell aggregation shows that NTRI and NEGR1 homo- and heterodimerize in trans. Taken together, we report 89 unpublished cell-surface ligand-receptor pairs and describe structural models of trans interactions of IgLONs, showing that their structures are compatible with a model of interaction across the synaptic cleft. Many aspects of synapse formation, specification, and maturation rely on interactions among a rich repertoire of cell-surface glycoproteins with adhesive and repulsive properties. Although the identity of these proteins is known, their network of interactions remains largely untapped. Ranaivoson et al. have identified a number of protein-protein interactions and have determined the structures of three members of the IgLONs, a family of five proteins of the immunoglobulin superfamily that has recently been implicated in a wide range of human disease.

Original languageEnglish (US)
Pages (from-to)893-906.e9
Issue number6
StatePublished - Jun 4 2019
Externally publishedYes


  • IgLON
  • SAXS
  • ligand-receptor pair
  • protein crystallography

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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