Structure and Ca2+-binding properties of the tandem C 2 Domains of E-Syt2

Junjie Xu, Taulant Bacaj, Amy Zhou, Diana R Tomchick, Thomas C. Südhof, Jose Rizo-Rey

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Contacts between the endoplasmic reticulum and the plasma membrane involve extended synaptotagmins (E-Syts) in mammals or tricalbins in yeast, proteins with multiple C2 domains. One of the tandem C2 domains of E-Syt2 is predicted to bind Ca2+, but no Ca2+-dependent function has been attributed to this protein. We have determined the crystal structures of the tandem C2 domains of E-Syt2 in the absence and presence of Ca2+ and analyzed their Ca2+-binding properties by nuclear magnetic resonance spectroscopy. Our data reveal an unexpected V-shaped structure with a rigid orientation between the two C 2 domains that is not substantially altered by Ca2+. The E-Syt2 C2A domain binds up to four Ca2+ ions, whereas the C2B domain does not bind Ca2+. These results suggest that E-Syt2 performs an as yet unidentified Ca2+-dependent function through its C2A domain and uncover fundamental differences between the properties of the tandem C2 domains of E-Syts and synaptotagmins.

Original languageEnglish (US)
Pages (from-to)269-280
Number of pages12
Issue number2
StatePublished - Feb 4 2014

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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