GSK-3 beta inhibits presynaptic vesicle exocytosis by phosphorylating P/Q-type calcium channel and interrupting SNARE complex formation.
Glycogen synthase kinase-3 (GSK-3), a Ser/Thr protein kinase abundantly expressed in neurons, plays diverse functions in physiological and neurodegenerative conditions. Our recent study shows that upregulation of GSK-3 suppresses long-term potentiation and presynaptic release of glutamate; however, the underlying mechanism is elusive. Here, we show that activation of GSK-3beta retards the synaptic vesicle exocytosis in response to membrane depolarization. Using calcium imaging, whole-cell patch-clamp, as well as specific Ca(2+) channel inhibitors, we demonstrate that GSK-3beta phosphorylates the intracellular loop-connecting domains II and III (L(II-III)) of P/Q-type Ca(2+) channels, which leads to a decrease of intracellular Ca(2+) rise through the P/Q-type voltage-dependent calcium channel. To further illustrate the mechanisms of GSK-3beta's action, we show that activation of GSK-3beta interferes with the formation of the soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (SNARE) complex through: (1) weakening the association of synaptobrevin with SNAP25 and syntaxin; (2) reducing the interactions among the phosphorylated L(II-III) and synaptotagmin, SNAP25, and syntaxin; and (3) inhibiting dissociation of synaptobrevin from synaptophysin I. These results indicate that GSK-3beta negatively regulates synaptic vesicle fusion events via interfering with Ca(2+)-dependent SNARE complex formation.
Zhu
Ling-Qiang
LQ
Department of Pathophysiology, Institute of Neuroscience, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
Liu
Dan
D
Hu
Juan
J
Cheng
Jin
J
Wang
Shao-Hui
SH
Wang
Qun
Q
Wang
Fang
F
Chen
Jian-Guo
JG
Wang
Jian-Zhi
JZ
D000595:Amino Acid Sequence; D000818:Animals; D020865:Calcium Channels, P-Type / Q000378:metabolism*; D020907:Calcium Channels, Q-Type / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D005089:Exocytosis / Q000502:physiology; D038362:Glycogen Synthase Kinase 3 / Q000096:biosynthesis / Q000502:physiology*; D000071679:Glycogen Synthase Kinase 3 beta; D008969:Molecular Sequence Data; D009433:Neural Inhibition / Q000502:physiology; D010766:Phosphorylation; D017729:Presynaptic Terminals / Q000378:metabolism*; D051381:Rats; D050600:SNARE Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D013572:Synaptic Vesicles / Q000378:metabolism*
D020865:Calcium Channels, P-Type; D020907:Calcium Channels, Q-Type; D050600:SNARE Proteins; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D038362:Glycogen Synthase Kinase 3