Crystal structure of the second LNS/LG domain from neurexin 1α: Ca2+ binding and the effects of alternative splicing

Lauren R. Sheckler, Lisa Henry, Shuzo Sugita, Thomas C. Südhof, Gabby Rudenko

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

Neurexins mediate protein interactions at the synapse, playing an essential role in synaptic function. Extracellular domains of neurexins, and their fragments, bind a distinct profile of different proteins regulated by alternative splicing and Ca2+. The crystal structure of n1α_LNS#2 (the second LNS/LG domain of bovine neurexin 1α) reveals large structural differences compared with n1α_LNS#6 (or n1β_LNS), the only other LNS/LG domain for which a structure has been determined. The differences overlap the so-called hyper-variable surface, the putative protein interaction surface that is reshaped as a result of alternative splicing. A Ca2+-binding site is revealed at the center of the hyper-variable surface next to splice insertion sites. Isothermal titration calorimetry indicates that the Ca2+-binding site in n1α_LNS#2 has low affinity (Kd∼400 μM). Ca2+ binding ceases to be measurable when an 8- or 15-residue splice insert is present at the splice site SS#2 indicating that alternative splicing can affect Ca2+-binding sites of neurexin LNS/LG domains. Our studies initiate a framework for the putative protein interaction sites of neurexin LNS/LG domains. This framework is essential to understand how incorporation of alternative splice inserts expands the information from a limited set of neurexin genes to produce a large array of synaptic adhesion molecules with potentially very different synaptic function.

Original languageEnglish (US)
Pages (from-to)22896-22905
Number of pages10
JournalJournal of Biological Chemistry
Volume281
Issue number32
DOIs
StatePublished - Aug 11 2006

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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