RIM1 confers sustained activity and neurotransmitter vesicle anchoring to presynaptic Ca2+ channels.
The molecular organization of presynaptic active zones is important for the neurotransmitter release that is triggered by depolarization-induced Ca2+ influx. Here, we demonstrate a previously unknown interaction between two components of the presynaptic active zone, RIM1 and voltage-dependent Ca2+ channels (VDCCs), that controls neurotransmitter release in mammalian neurons. RIM1 associated with VDCC beta-subunits via its C terminus to markedly suppress voltage-dependent inactivation among different neuronal VDCCs. Consistently, in pheochromocytoma neuroendocrine PC12 cells, acetylcholine release was significantly potentiated by the full-length and C-terminal RIM1 constructs, but membrane docking of vesicles was enhanced only by the full-length RIM1. The beta construct beta-AID dominant negative, which disrupts the RIM1-beta association, accelerated the inactivation of native VDCC currents, suppressed vesicle docking and acetylcholine release in PC12 cells, and inhibited glutamate release in cultured cerebellar neurons. Thus, RIM1 association with beta in the presynaptic active zone supports release via two distinct mechanisms: sustaining Ca2+ influx through inhibition of channel inactivation, and anchoring neurotransmitter-containing vesicles in the vicinity of VDCCs.
Kiyonaka
Shigeki
S
Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Kyoto 615-8510, Japan.
Wakamori
Minoru
M
Miki
Takafumi
T
Uriu
Yoshitsugu
Y
Nonaka
Mio
M
Bito
Haruhiko
H
Beedle
Aaron M
AM
Mori
Emiko
E
Hara
Yuji
Y
De Waard
Michel
M
Kanagawa
Motoi
M
Itakura
Makoto
M
Takahashi
Masami
M
Campbell
Kevin P
KP
Mori
Yasuo
Y
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D019204:GTP-Binding Proteins / Q000502:physiology*; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009474:Neurons / Q000166:cytology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000502:physiology*; D021122:Protein Subunits / Q000378:metabolism; D050765:Qa-SNARE Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000502:physiology*; D014162:Transfection / Q000379:methods; D020798:Two-Hybrid System Techniques; D050994:Voltage-Dependent Anion Channels / Q000502:physiology*
D009419:Nerve Tissue Proteins; D018377:Neurotransmitter Agents; D021122:Protein Subunits; D050765:Qa-SNARE Proteins; C107293:Rim protein, mammalian; D050994:Voltage-Dependent Anion Channels; D019204:GTP-Binding Proteins; D002118:Calcium