Local, persistent activation of Rho GTPases during plasticity of single dendritic spines

Even brief neuronal activity can result in long-term potentiation (LTP) of synapses, which is associated with enlargement of dendritic spines on the neuron at the receiving end of neurotransmission. Using live imaging of fluorescently tagged signalling proteins in individual spines, Ryohei Yasuda and colleagues show that transient activation of the Ca2+/calmodulin-dependent kinase (CaMKII) is translated into short-term versus long-term and long-range (dendritic) versus short-range (spine-confined) signalling, depending on which small GTPase of the Rho family is activated. The technique is bringing the study of the cellular bases of learning and memory down to the nanometre scale.