On Mar.16, 2021, Yao Jun's Group published 'Synaptotagmin-1 interacts with PI(4,5)P2 to initiate synaptic vesicle docking in hippocampal neurons' in Cell Reports.
- Syt1 corralled SVs within ∼12 nm to the AZ to initiate SV docking
- PI(4,5)P2 functioned as the membrane partner of Syt1 to dock SVs
- Syt1 and PI(4,5)P2 functioned prior to the SNARE complex formation
Synaptic vesicle (SV) docking is a dynamic multi-stage process that is required for efficient neurotransmitter release in response to nerve impulses. Although the steady-state SV docking likely involves the cooperation of Synaptotagmin-1 (Syt1) and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), where and how the docking process initiates remains unknown. Phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) can interact with Syt1 and SNAREs to contribute to vesicle exocytosis. In the present study, using the CRISPRi-mediated multiplex gene knockdown and 3D electron tomography approaches, we show that in mouse hippocampal synapses, SV docking initiates at ∼12 nm to the active zone (AZ) by Syt1. Furthermore, we demonstrate that PI(4,5)P2 is the membrane partner of Syt1 to initiate SV docking, and disrupting their interaction could abolish the docking initiation. In contrast, the SNARE complex contributes only to the tight SV docking within 0–2 nm. Therefore, Syt1 interacts with PI(4,5)P2 to loosely dock SVs within 2–12 nm to the AZ in hippocampal neurons.