Illuminating the Mechanisms Behind Neuronal "Learning"

The strength of each of the thousands of synapses in a given neuron can be rapidly and independently modified in response to experience. What scientists do not yet understand is how distinct synapses distributed along neuronal processes - branches of a neuron which can project far from the cell body - are supplied with the appropriate type and number of neurotransmitter receptors. Previous studies from the laboratory of University of Utah Health scientist Andres Villu Maricq, MD, PhD, provided insight into this problem by showing that the delivery and removal of AMPA-type ionotropic glutamate receptors (AMPARs) to and from synapses depends on transport by kinesin protein motors. More recently, Maricq and colleagues have demonstrated that the coordinated activities of two major signaling pathways converge on a complex of scaffold proteins to regulate the loading of AMPAR cargo onto kinesin motors, thereby providing a mechanism to explain the rapid exchange of AMPARs in response to synaptic activity. These findings reveal mechanisms underlying the control of cellular transport, and have important implications for cellular models of learning and memory.