Proteomic Assays of Neuronal Protein Palmitoylation

William N. Green, Department of Neurobiology, University of Chicago

Protein palmitoylation is a reversible, post-translational process in which the fatty acid, palmitate, is linked covalently to proteins. As a result, palmitoylation regulates membrane association of proteins and their partitioning into membrane domains such as lipid rafts. There is mounting evidence that palmitoylation has a major role in neuronal development and function, in particular, the formation, regulation and functioning of synapses. Because synapses in brain reward regions are thought to undergo changes that underlie drug abuse we would like to examine whether palmitoylation of synaptic proteins and/or their regulatory proteins changes during drug abuse. The animal model of drug abuse to be used is the phenomenon of sensitization induced in rats by exposure to amphetamine. We have recently developed new techniques for assaying protein palmitoylation that are quantitative and more sensitive than other approaches. Furthermore, these techniques can be used to assay the palmitoylation of proteins from brain for the first time.

The main objective of these proposed experiments is to develop proteomic assays based on our new techniques that will address questions about the palmitoylation of ionotropic neurotransmitter receptors and the palmitoylation of proteins found in large-scale protein preparations from brain such as postsynaptic densities (PSDs) and lipid rafts. New proteomic-based technology will be developed to assay a protein post-translational modification. Ultimately we hope to use these techniques to characterize the role of palmitoylation in the molecular mechanisms underlying drug abuse. Specifically, we plan to use these techniques to assay for the synaptic proteins isolated from rat nucleus accumbens that undergo changes in their palmitoylation with amphetamine exposure.