Duncan J A, Gilman A G
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
J Biol Chem. 1996 Sep 20;271(38):23594-600. doi: 10.1074/jbc.271.38.23594.
The palmitoylation or S-acylation of at least some G protein alpha subunits is a dynamic process that is regulated in vivo by the activation of associated receptors. Highly purified, myristoylated Gialpha1 and other G protein alpha subunits react spontaneously with palmitoyl-CoA in vitro to form thioesterified proteins. This reaction requires native Gialpha1 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 betagamma subunit complex. Autoacylation may play a role in the dynamic thioesterification of some cellular proteins.
至少某些G蛋白α亚基的棕榈酰化或S-酰化是一个动态过程，在体内受相关受体激活的调控。高度纯化的、肉豆蔻酰化的Gialpha1和其他G蛋白α亚基在体外能与棕榈酰辅酶A自发反应，形成硫酯化蛋白。该反应需要天然的Gialpha1，且仅发生在Cys3处，这与体内棕榈酰化的残基相同。反应会进行到底，其速率大致等同于体内脉冲追踪实验中观察到的棕榈酸酯丢失速率。G蛋白βγ亚基复合物能显著提高自身酰化速率。自身酰化可能在某些细胞蛋白的动态硫酯化过程中发挥作用。
