Functional Analysis of Protein S-Palmitoylation Enzymes.

[摘要] Protein S-palmitoylation is a dynamic, hydrophobic, post-translational modification of cysteine residues that is required for the spatiotemporal organization of hundreds of proteins. In turn, protein palmitoylation contributes to the composition of cellular membrane environments and plays fundamental roles in cancer, neurological disorders and many other human diseases.Despite its central function in human pathology, still, little is known about the enzymes that catalyze the addition (protein S-acyl transferases) and removal (S-acyl protein thioesterases) of this modification. The two enzyme families, DHHCs and LYPLAs, are thought to make up the so-called dynamic palmitoylation machinery in which dual action of acyltransferases and thioesterases promote proper membrane targeting for an expanding list of dynamically palmitoylated proteins. Indeed, a steady growth in studies of these enzymes is beginning to shed light on their biological functions, revealing that the interplay between these opposing catalysts may be more complex than previously thought. More specific tools for these enzymes can therefore provide a more complete molecular description of dynamic palmitoylation events and its regulation in various biological settings. The work presented in this thesis explores the chemical mechanisms and physiological roles of DHHCs and LYPLAs by developing, characterizing and employing novel tools for their study in the context of cancer biology. In the second chapter, the cellular targets of a widely-used, mechanism-based protein acyltransferase inhibitor are profiled and analyzed. In the third chapter, a mechanistic description of divergent thioesterase active-site ligand specificities is presented using both a structural and a kinetic approach. In the third chapter, novel acyl-protein thioesterase inhibitors are applied to define their roles in organizing cell junctions and suppressing metastatic transformation. One of the fundamental goals in this thesis is to address the limitations of current chemical tools of protein palmitoylation and provide a framework for the development of selective pharmacological agents to accelerate the study of this modification. From a physiological standpoint, this work offers novel insights into the in vivo functions of palmitoyl transferases and de-palmitoylases, highlighting the intricacies of the regulatory system governing the palmitoylation state of a given protein.

[发布机构] University of Michigan

[效力级别] Protein S-acyltransferase

[关键词] Dynamic S-Acylation;Protein S-acyltransferase;Acyl-protein thioesterase;Cancer and epithelial-mesenchymal transition;Protein S-palmitoylation probes and inhibitors;Biological Chemistry;Pharmacy and Pharmacology;Chemistry;Health Sciences;Science;Chemical Biology