Selective Enrichment and Direct Analysis of Protein S-Palmitoylation Sites

J Proteome Res. 2018 May 4;17(5):1907-1922. doi: 10.1021/acs.jproteome.8b00002. Epub 2018 Apr 6.


S-Fatty-acylation is the covalent attachment of long chain fatty acids, predominately palmitate (C16:0, S-palmitoylation), to cysteine (Cys) residues via a thioester linkage on proteins. This post-translational and reversible lipid modification regulates protein function and localization in eukaryotes and is important in mammalian physiology and human diseases. While chemical labeling methods have improved the detection and enrichment of S-fatty-acylated proteins, mapping sites of modification and characterizing the endogenously attached fatty acids are still challenging. Here, we describe the integration and optimization of fatty acid chemical reporter labeling with hydroxylamine-mediated enrichment of S-fatty-acylated proteins and direct tagging of modified Cys residues to selectively map lipid modification sites. This afforded improved enrichment and direct identification of many protein S-fatty-acylation sites compared to previously described methods. Notably, we directly identified the S-fatty-acylation sites of IFITM3, an important interferon-stimulated inhibitor of virus entry, and we further demonstrated that the highly conserved Cys residues are primarily modified by palmitic acid. The methods described here should facilitate the direct analysis of protein S-fatty-acylation sites and their endogenously attached fatty acids in diverse cell types and activation states important for mammalian physiology and diseases.

Keywords: S-palmitoylation; affinity enrichment; fatty acylation; mass spectrometry-based proteomics; posttranslational modification; site identification.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acylation
  • Animals
  • Binding Sites
  • Cysteine / metabolism*
  • Fatty Acids / metabolism
  • Humans
  • Hydroxylamine
  • Lipoylation*
  • Mass Spectrometry
  • Membrane Proteins / metabolism
  • Palmitic Acid / metabolism*
  • Protein Processing, Post-Translational*
  • Proteomics / methods*
  • RNA-Binding Proteins / metabolism
  • Staining and Labeling


  • Fatty Acids
  • IFITM3 protein, human
  • Membrane Proteins
  • RNA-Binding Proteins
  • Hydroxylamine
  • Palmitic Acid
  • Cysteine