RIM C₂B Domains Target Presynaptic Active Zone Functions to PIP₂-Containing Membranes.

ABSTRACT: Rapid and efficient synaptic vesicle fusion requires a pool of primed vesicles, the nearby tethering of Ca²⁺ channels, and the presence of the phospholipid PIP₂ in the target membrane. Although the presynaptic active zone mediates the first two requirements, it is unclear how fusion is targeted to membranes with high PIP₂ content. Here we find that the C₂B domain of the active zone scaffold RIM is critical for action potential-triggered fusion. Remarkably, the known RIM functions in vesicle priming and Ca²⁺ influx do not require RIM C₂B domains. Instead, biophysical experiments reveal that RIM C₂ domains, which lack Ca²⁺ binding, specifically bind to PIP₂. Mutational analyses establish that P

SUBMITTER: de Jong APH 

PROVIDER: S-EPMC5910229 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature