TY - JOUR
T1 - α-Latrotoxin stimulates a novel pathway of Ca2+-dependent synaptic exocytosis independent of the classical synaptic fusion machinery
AU - Deák, Ferenc
AU - Liu, Xinran
AU - Khvotchev, Mikhail
AU - Li, Gang
AU - Kavalali, Ege T.
AU - Sugita, Shuzo
AU - Südhof, Thomas C.
PY - 2009/7/8
Y1 - 2009/7/8
N2 - α-Latrotoxin induces neurotransmitter release by stimulating synaptic vesicle exocytosis via two mechanisms: (1) A Ca2+-dependent mechanism with neurexins as receptors, in which α-latrotoxin acts like a Ca2+ ionophore, and (2) a Ca2+-independent mechanism with CIRL/latrophilins as receptors, in which α-latrotoxin directly stimulates the transmitter release machinery. Here, we show that the Ca2+- independent release mechanism by α-latrotoxin requires the synaptic SNARE-proteins synaptobrevin/VAMP and SNAP-25, and, at least partly, the synaptic active-zone protein Munc13-1. In contrast, the Ca2+- dependent release mechanism induced by α-latrotoxin does not require any of these components of the classical synaptic release machinery. Nevertheless, this type of exocytotic neurotransmitter release appears to fully operate at synapses, and to stimulate exocytosis of the same synaptic vesicles that participate in physiological action potential-triggered release. Thus, synapses contain two parallel and independent pathways of Ca2+-triggered exocytosis, a classical, physiological pathway that operates at the active zone, and a novel reserve pathway that is recruited only when Ca2+ floods the synaptic terminal.
AB - α-Latrotoxin induces neurotransmitter release by stimulating synaptic vesicle exocytosis via two mechanisms: (1) A Ca2+-dependent mechanism with neurexins as receptors, in which α-latrotoxin acts like a Ca2+ ionophore, and (2) a Ca2+-independent mechanism with CIRL/latrophilins as receptors, in which α-latrotoxin directly stimulates the transmitter release machinery. Here, we show that the Ca2+- independent release mechanism by α-latrotoxin requires the synaptic SNARE-proteins synaptobrevin/VAMP and SNAP-25, and, at least partly, the synaptic active-zone protein Munc13-1. In contrast, the Ca2+- dependent release mechanism induced by α-latrotoxin does not require any of these components of the classical synaptic release machinery. Nevertheless, this type of exocytotic neurotransmitter release appears to fully operate at synapses, and to stimulate exocytosis of the same synaptic vesicles that participate in physiological action potential-triggered release. Thus, synapses contain two parallel and independent pathways of Ca2+-triggered exocytosis, a classical, physiological pathway that operates at the active zone, and a novel reserve pathway that is recruited only when Ca2+ floods the synaptic terminal.
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U2 - 10.1523/JNEUROSCI.0898-09.2009
DO - 10.1523/JNEUROSCI.0898-09.2009
M3 - Article
C2 - 19587270
AN - SCOPUS:67650503006
SN - 0270-6474
VL - 29
SP - 8639
EP - 8648
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 27
ER -