Modulation of Presynaptic Release Probability by the Vertebrate-Specific Protein Mover
Authors: Körber C, Horstmann H, Venkataramani V, Herrmannsdörfer F, Kremer T, Kaiser M, Schwenger DB, Ahmed S, Dean C, Dresbach T, Kuner T
CellNetworks People: Kuner Thomas
Journal: Neuron. 2015 Aug 5;87(3):521-33. doi: 10.1016/j.neuron.2015.07.001. Epub 2015 Jul 23.

Mover, a member of the exquisitely small group of vertebrate-specific presynaptic proteins, has been discovered as an interaction partner of the scaffolding protein Bassoon, yet its function has not been elucidated. We used adeno-associated virus (AAV)-mediated shRNA expression to knock down Mover in the calyx of Held in vivo. Although spontaneous synaptic transmission remained unaffected, we found a strong increase of the evoked EPSC amplitude. The size of the readily releasable pool was unaltered, but short-term depression was accelerated and enhanced, consistent with an increase in release probability after Mover knockdown. This increase in release probability was not caused by alterations in Ca(2+) influx but rather by a higher Ca(2+) sensitivity of the release machinery, as demonstrated by presynaptic Ca(2+) uncaging. We therefore conclude that Mover expression in certain subsets of synapses negatively regulates synaptic release probability, constituting a novel mechanism to tune synaptic transmission.