Activity-dependent synaptic localization of processing bodies and their role in dendritic structural plasticity.

In neurons, transport of a subset of mRNAs to subcellular regions and their translation has a role in synaptic plasticity. Recent studies have suggested a control mechanism of this local translation through mRNA compartmentalization or degradation. Here we report that processing bodies (P-bodies), which are involved in mRNA degradation or storage, are transported to dendrites by conventional kinesin (KIF5A) as a motor protein. Neuronal activation induced by depolarization increased the colocalization of P-bodies with PSD-95 in dendrites. This neuronal activity increased the release of Nd1 and Arp2 mRNA from the P-bodies and, consequently, reversed the decrease of F-actin (induced by overexpression of Dcp1a) in the dendrites. Our data suggest that the activity-induced redistribution of P-bodies and mRNA release from P-bodies might have a role in synaptic structural plasticity by altering levels of mRNAs that are involved in the dynamics of the actin cytoskeleton in dendrites.