An S-acylation switch of conserved G domain cysteines is required for polarity signaling by ROP GTPases

Curr Biol. 2010 May 25;20(10):914-20. doi: 10.1016/j.cub.2010.03.057. Epub 2010 May 6.


Rho GTPases are master regulators of cell polarity. For their function, Rhos must associate with discrete plasma membrane domains. Rho of Plants (ROPs) or RACs comprise a single family. Prenylation and S-acylation of hypervariable domain cysteines of Ras and Rho GTPases are required for their function; however, lipid modifications in the G domain have never been reported. Reversible S-acylation involves the attachment of palmitate (C16:0) or other saturated lipids to cysteines through a thioester linkage and was implicated in the regulation of signaling. Here we show that transient S-acylation of Arabidopsis AtROP6 takes place on two conserved G domain cysteine residues, C21 and C156. C21 is relatively exposed and is accessible for modification, but C156 is not, implying that its S-acylation involves a conformational change. Fluorescence recovery after photobleaching beam-size analysis shows that S-acylation of AtROP6 regulates its membrane-association dynamics, and detergent-solubilization studies indicate that it regulates AtROP6 association with lipid rafts. Site-specific acylation-deficient AtROP6 mutants can bind and hydrolyze GTP but display compromised effects on polar cell growth, endocytic uptake of the tracer dye FM4-64, and distribution of reactive oxygen species. These data reveal an S-acylation switch that regulates Rho signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acylation
  • Arabidopsis / cytology
  • Arabidopsis / enzymology
  • Arabidopsis / physiology
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism
  • Cell Polarity*
  • Cysteine / metabolism*
  • Lipid Metabolism
  • Membrane Microdomains / chemistry
  • Membrane Microdomains / metabolism
  • Models, Molecular
  • Monomeric GTP-Binding Proteins / chemistry
  • Monomeric GTP-Binding Proteins / genetics
  • Monomeric GTP-Binding Proteins / metabolism*
  • Palmitic Acid / metabolism
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction / physiology*
  • Stearic Acids / metabolism


  • Arabidopsis Proteins
  • ROP6 protein, Arabidopsis
  • Recombinant Fusion Proteins
  • Stearic Acids
  • Palmitic Acid
  • stearic acid
  • Monomeric GTP-Binding Proteins
  • Cysteine