Relevance of presynaptic actin dynamics for synapse function and mouse behavior.

Actin is the most abundant cytoskeletal protein in presynaptic terminals as well as in postsynaptic dendritic spines of central excitatory synapses. While the relevance of actin dynamics for postsynaptic plasticity, for instance activity-induced changes in dendritic spine morphology and synaptic glutamate receptor mobility, is well-documented, only little is known about its function and regulatory mechanisms in presynaptic terminals. Moreover, studies on presynaptic actin dynamics have often been inconsistent, suggesting that actin has diverse presynaptic functions, varying likely between specific types of excitatory synapses and/or their activity states. In this review, we will summarize and discuss the function and upstream regulatory mechanisms of the actin cytoskeleton in presynaptic terminals, focusing on excitatory synapses of the mammalian central nervous system. Due to length restrictions we will mainly concentrate on new insights into actin's presynaptic function that have been gained by cell biological and mouse genetic approaches since the excellent 2008 review by Cingolani and Goda.