Myristoylome Profiling Reveals a Concerted Mechanism of ARF GTPase Deacylation by the Bacterial Protease IpaJ

• DOI: 10.1016/j.molcel.2015.01.040
• Publication Date: 2015-03-12T11:53:39Z
• Authors: Nikolay Burnaevskiy; Tao Peng; L. Evan Reddick; Howard C. Hang; Neal M. Alto
• Keywords: Models, Molecular; Protein Conformation; Molecular Sequence Data; Crystallography, X-Ray; Myristic Acid; Shigella flexneri; 03 medical and health sciences; Escherichia coli; Humans; Amino Acid Sequence; Molecular Biology; Antigens, Bacterial; 0303 health sciences; ADP-Ribosylation Factors; Cell Biology; Recombinant Proteins; Protein Structure, Tertiary; 3. Good health; ADP-Ribosylation Factor 6; ADP-Ribosylation Factor 1; Hydrophobic and Hydrophilic Interactions; Protein Processing, Post-Translational; HeLa Cells; Protein Binding; Signal Transduction

N-myristoylation is an essential fatty acid modification that governs the localization and activity of cell signaling enzymes, architectural proteins, and immune regulatory factors. Despite its importance in health and disease, there are currently no methods for reversing protein myristoylation in vivo. Recently, the Shigella flexneri protease IpaJ was found to cleave myristoylated glycine of eukaryotic proteins, yet the discriminatory mechanisms of substrate selection required for targeted demyristoylation have not yet been evaluated. Here, we performed global myristoylome profiling of cells treated with IpaJ under distinct physiological conditions. The protease is highly promiscuous among diverse N-myristoylated proteins in vitro but is remarkably specific to Golgi-associated ARF/ARL family GTPases during Shigella infection. Reconstitution studies revealed a mechanistic framework for substrate discrimination based on IpaJ's function as a GTPase "effector" of bacterial origin. We now propose a concerted model for IpaJ function that highlights its potential for programmable demyristoylation in vivo.