Proteolytic maturation of α<sub>2</sub>δ controls the probability of synaptic vesicular release.

Ferron, Laurent; Kadurin, Ivan; Dolphin, Annette C · Elife · 2018

basic_science · Level V

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Abstract

Auxiliary α<sub>2</sub>δ subunits are important proteins for trafficking of voltage-gated calcium channels (Ca<sub>V</sub>) at the active zones of synapses. We have previously shown that the post-translational proteolytic cleavage of α<sub>2</sub>δ is essential for their modulatory effects on the trafficking of N-type (Ca<sub>V</sub>2.2) calcium channels (Kadurin et al., 2016). We extend these results here by showing that the probability of presynaptic vesicular release is reduced when an uncleaved α<sub>2</sub>δ is expressed in rat neurons and that this inhibitory effect is reversed when cleavage of α<sub>2</sub>δ is restored. We also show that asynchronous release is influenced by the maturation of α<sub>2</sub>δ-1, highlighting the role of Ca<sub>V</sub> channels in this component of vesicular release. We present additional evidence that Ca<sub>V</sub>2.2 co-immunoprecipitates preferentially with cleaved wild-type α<sub>2</sub>δ. Our data indicate that the proteolytic maturation increases the association of α<sub>2</sub>δ-1 with Ca<sub>V</sub> channel complex and is essential for its function on synaptic release.

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