Kelsey C. Martin

Kelsey Martin, Professor in the Department of Biological Chemistry, Eleanor Leslie Term Chair in Innovative Brain Research, and Co-Director of the UCLA-Caltech Medical Scientist Training Program (MSTP), is interested in the molecular and cell biology of learning and memory. Her lab studies long-term synaptic plasticity, the process whereby neurons change the strength and number of their synaptic connections with experience. Long-term forms of synaptic plasticity, like long-term memory, require new gene expression. The Martin lab focuses on two questions that emerge from this requirement: 1) how are signals received at distal synapses relayed to the nucleus to turn on transcription? and 2) how can gene expression be spatially restricted within the neuron to allow synapse-specific forms of transcription-dependent plasticity? They study these questions using two model systems of learning-related synaptic plasticity: Aplysia sensory-motor synapses and rodent hippocampal synapses, using a combination of electrophysiology, biochemistry, cell and molecular biology. In 2004, the Martin lab discovered a role for importin-mediated active nuclear transport in carrying signals from the synapse to the nucleus during long-term synaptic plasticity. Current efforts are focused on identifying the synaptically-localized protein cargoes of importins and on understanding the cell biological pathway underlying this long-distance retrograde transport. In 1997, Kelsey Martin discovered that synapse-specific forms of long-term plasticity require translation of localized mRNAs at the synapse. The Martin lab has since identified a large population of mRNAs that are present in neurites of Aplysia sensory neurons and and dendrites of rodent hippocampal neurons. Using a combination of in situ hybridization, live cell imaging of RNA and translational reporters, siRNA-mediated gene silencing and electrophysiological recording, they are investigating the mechanisms underlying mRNA localization and regulated translation in neurons as well as the function of this form of regulated gene expression during synapse formation and synaptic plasticity. The goal of these studies is to understand how the brain forms and stores memories, and to provide insights into the pathophysiology of disorders in which learning and memory are impaired.