Effect of N-Terminal Myristoylation on the Active Conformation of Gαi1-GTP

Biochemistry. 2017 Jan 10;56(1):271-280. doi: 10.1021/acs.biochem.6b00388. Epub 2016 Dec 29.

Abstract

G proteins are part of the G-protein-coupled receptor (GPCR) signal transduction cascade in which they transfer a signal from the membrane-embedded GPCR to other proteins in the cell. In the case of the inhibitory G-protein heterotrimer, permanent N-terminal myristoylation can transiently localize the Gαi subunit at the membrane as well as crucially influence Gαi's function in the GTP-bound conformation. The attachment of lipids to proteins is known to be essential for membrane trafficking; however, our results suggest that lipidation is also important for protein-protein interactions during signal transduction. Here we investigate the effect of myristoylation on the structure and dynamics of soluble Gαi1 and its possible implication for signal transduction. A 2 μs classical molecular dynamics simulation of a myristoylated Gαi1-GTP complex suggests that the myristoyl-induced conformational changes of the switch II and alpha helical domains create new possibilities for protein-protein interactions and emphasize the importance of permanent lipid attachment for the conformation and functional tunability of signaling proteins.

MeSH terms

  • ADP-Ribosylation Factor 1 / chemistry
  • ADP-Ribosylation Factor 1 / genetics
  • ADP-Ribosylation Factor 1 / metabolism
  • Amino Acid Sequence
  • Animals
  • Crystallography, X-Ray
  • GTP-Binding Protein alpha Subunits, Gi-Go / chemistry*
  • GTP-Binding Protein alpha Subunits, Gi-Go / genetics
  • GTP-Binding Protein alpha Subunits, Gi-Go / metabolism
  • Guanosine 5'-O-(3-Thiotriphosphate) / chemistry
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Guanosine Diphosphate / chemistry
  • Guanosine Diphosphate / metabolism
  • Guanosine Triphosphate / chemistry*
  • Guanosine Triphosphate / metabolism
  • Molecular Conformation
  • Molecular Dynamics Simulation
  • Myristic Acid / chemistry*
  • Myristic Acid / metabolism
  • Protein Binding
  • Protein Conformation*
  • Protein Domains
  • Protein Structure, Secondary
  • Rats
  • Sequence Homology, Amino Acid
  • Static Electricity

Substances

  • Myristic Acid
  • Guanosine Diphosphate
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Guanosine Triphosphate
  • GTP-Binding Protein alpha Subunits, Gi-Go
  • ADP-Ribosylation Factor 1