Functional Analyses of ABHD17 Enzymes

Abstract

Post-translational modifications (PTMs) play a crucial role in trafficking proteins for many location-dependent cellular functions. Protein S-acylation describes the addition of long chain fatty acids (predominantly the C16:0 palmitate) to cysteines via a thioester bond. This reversible modification thus allows for controlled regulation of protein membrane tethering during various cellular processes. Indeed, S-palmitoylated proteins include kinases, small GTPases and transmembrane receptors, which function in response to diverse signaling events. It is important to study the enzymes that catalyze this modification since it is involved in many essential pathways. Enzymes such as APT1 and APT2 have thoroughly been studied and shown to depalmitoylate a myriad of S-palmitoylated substrates and the development of selective inhibitors has accelerated the discovery of new substrates. ABHD17 has more recently been shown to depalmitoylate substrates in cell-based studies. However, not much is known about its substrate recognition mechanism and cellular function and my dissertation helps to bridge this gap in knowledge. The first chapter presents a detailed introduction to protein depalmitoylases, their different cellular roles and methods that have been developed to study them. The following chapter focuses on understanding the in vitro activity of ABHD17 and the development of potential inhibitors to study its function. The third chapter outlines a proteomics strategy that can be used to study S-palmitoylation of multiple proteins at a time and was applied to understand how ABHD17 regulates S-palmitoylation in cells. Finally, future experiments are proposed in Chapter 4 to further improve our understanding of how ABHD17 works and what its cellular function is.