Autoacylation of G protein α subunits

The palmitoylation or S-acylation of at least some G protein α subunits is a dynamic process that is regulated in vivo by the activation of associated receptors. Highly purified, myristoylated G[α] and other G protein a subunits react spontaneously with palmitoyl-CoA in vitro to form thioesterified proteins. This reaction requires native G[α] and occurs exclusively at Cys³, the same residue that is palmitoylated in vivo. The reaction proceeds to completion, and its rate is roughly equal to the rate of loss of palmitate observed in pulse-chase experiments in vivo. The rate of autoacylation is significantly enhanced by the G protein βγ subunit complex. Autoacylation may play a role in the dynamic thioesterification of some cellular proteins.