Understanding how post-translational palmitoylation influences in vivo molecular and circuit dynamics during learning

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Habituation is a simple form of learning in which animals reduce responsiveness to repetitive stimuli. Habituation forms a foundation for normal cognition; without the ability to filter irrelevant stimuli, animals are unable to perform more complex cognitive tasks. Indeed, habituation learning is impaired in a wide range of heritable human disorders that present with more complex cognitive symptoms, including Schizophrenia, Autism Spectrum Disorders and Huntington’s Disease. Habituation learning is also a significant component of our innate decision-making: habituation to particular foods or drugs of abuse influences our responses to these stimuli and our decisions to seek them. Beyond its relevance for human behavior and disease, habituation can provide a simple and accessible model for examining some of the most exciting mysteries that inspired the BRAIN initiative, such as how proteins are mobilized during learning to alter synapses, circuits and behavior. Despite great interest, decades of study, and relevance for human disease, there are still significant gaps in our understanding of habituation learning. This proposal is based on the candidate’s discovery that post-translational palmitoylation plays a critical role in habituation learning. Specifically, using the larval zebrafish, she has found that the palmitoyltransferase Hip14 targets the Shaker-like channel Kv1.1 to regulate learning. This novel learning pathway represents an entirely independent research niche from which the PI will establish her own laboratory. The Granato lab, although expert in behavioral genetics, has never systematically examined how post-translational modifications influence protein dynamics, synapses, and behavior in real time. The PI will receive training from world experts in palmitoylation (Dr. Eric Witze) and in vivo electrophysiology (Dr. Alberto Pereda), integrating these approaches into a well-rounded system to examine learning across genes, circuits, and behavior. The PI will be based in the laboratory of Dr. Michael Granato at the University of Pennsylvania for the entire K99 period. During this time, the PI will learn to perform electrophysiological recordings in vivo to identify how activity within individual neurons is dynamic during habituation learning, and how plasticity is disrupted in mutants lacking Hip14 or Kv1.1 (Aim 1). This approach will be combined with calcium imaging, unbiased whole brain activity mapping, and transgenic rescue experiments to identify new circuit loci for habituation learning. Simultaneously, the PI will perform biochemical and live imaging experiments to examine how protein palmitoylation changes during learning, and how palmitoylation affects target protein localization in vivo (Aim 2). Finally, the PI will conduct a candidate screen to identify additional learning-relevant targets for Hip14 palmitoylation (Aim 3). These efforts will establish a broad and independent foundation for the candidate’s independent career investigating how post-translational modifications influence synaptic plasticity within defined neural circuits as we learn.