Dissection of SNARE-driven membrane fusion and neuroexocytosis by wedging small hydrophobic molecules into the SNARE zipper.
Neuronal SNARE proteins mediate neurotransmitter release at the synapse by facilitating the fusion of vesicles to the presynaptic plasma membrane. Cognate v-SNAREs and t-SNAREs from the vesicle and the plasma membrane, respectively, zip up and bring about the apposition of two membranes attached at the C-terminal ends. Here, we demonstrate that SNARE zippering can be modulated in the midways by wedging with small hydrophobic molecules. Myricetin, which intercalated into the hydrophobic inner core near the middle of the SNARE complex, stopped SNARE zippering in motion and accumulated the trans-complex, where the N-terminal region of v-SNARE VAMP2 is in the coiled coil with the frayed C-terminal region. Delphinidin and cyanidin inhibited N-terminal nucleation of SNARE zippering. Neuronal SNARE complex in PC12 cells showed the same pattern of vulnerability to small hydrophobic molecules. We propose that the half-zipped trans-SNARE complex is a crucial intermediate waiting for a calcium trigger that leads to fusion pore opening.
School of Life Science and Biotechnology and Center for Human Interface Nanotechnology, Sungkyunkwan University, Suwon 440-746, South Korea.
Yoosoo
Y
Yang
Jae Yoon
JY
Shin
Jung-Mi
JM
Oh
Chang Hwa
CH
Jung
Yunha
Y
Hwang
Sehyun
S
Kim
Jun-Seob
JS
Kim
Kee-Jung
KJ
Yoon
Ji-Young
JY
Ryu
Jaeil
J
Shin
Jae Sung
JS
Hwang
Tae-Young
TY
Yoon
Yeon-Kyun
YK
Shin
Dae-Hyuk
DH
Kweon
D000818:Animals; D000872:Anthocyanins / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D057927:Hydrophobic and Hydrophilic Interactions / Q000187:drug effects; D008561:Membrane Fusion / Q000187:drug effects / Q000502:physiology*; D016716:PC12 Cells; D017434:Protein Structure, Tertiary; D051381:Rats; D050600:SNARE Proteins / Q000235:genetics / Q000378:metabolism*
D000872:Anthocyanins; D005419:Flavonoids; D050600:SNARE Proteins; C040015:myricetin; C017154:cyanidin; C017185:delphinidin; D002118:Calcium