%0 Journal Article
%T Ca2+ Regulates the Drosophila Stoned-A and Stoned-B Proteins Interaction with the C2B Domain of Synaptotagmin-1
%A Carolina Soekmadji
%A Clement Angkawidjaja
%A Leonard E. Kelly
%J PLOS ONE
%D 2012
%I Public Library of Science (PLoS)
%R 10.1371/journal.pone.0038822
%X The dicistronic Drosophila stoned gene is involved in exocytosis and/or endocytosis of synaptic vesicles. Mutations in either stonedA or stonedB cause a severe disruption of neurotransmission in fruit flies. Previous studies have shown that the coiled-coil domain of the Stoned-A and the ¦Ì-homology domain of the Stoned-B protein can interact with the C2B domain of Synaptotagmin-1. However, very little is known about the mechanism of interaction between the Stoned proteins and the C2B domain of Synaptotagmin-1. Here we report that these interactions are increased in the presence of Ca2+. The Ca2+-dependent interaction between the ¦Ì-homology domain of Stoned-B and C2B domain of Synaptotagmin-1 is affected by phospholipids. The C-terminal region of the C2B domain, including the tryptophan-containing motif, and the Ca2+ binding loop region that modulate the Ca2+-dependent oligomerization, regulates the binding of the Stoned-A and Stoned-B proteins to the C2B domain. Stoned-B, but not Stoned-A, interacts with the Ca2+-binding loop region of C2B domain. The results indicate that Ca2+-induced self-association of the C2B domain regulates the binding of both Stoned-A and Stoned-B proteins to Synaptotagmin-1. The Stoned proteins may regulate sustainable neurotransmission in vivo by binding to Ca2+-bound Synaptotagmin-1 associated synaptic vesicles.
%U http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0038822