Biologjia Online

In order to define the molecular steps involved in learning-related synaptic growth, Udo et al. demonstrate that the signaling pathway of ApCdc42, amember of the Rho GTPases, is required for the long-term changes in synaptic strength and structure induced by 5-HT at the sensory-motor neuron connection in Aplysia. 5-HT-induced activation of ApCdc42 in sensory neurons depends on the PI3 kinase and PLC pathways and recruits N-WASP and PAK to regulate the presynaptic actin network leading to the outgrowth of filopodia, which are precursors for the formation of new sensory neuron synapses associated with long-term facilitation.