Myristic acid (C14:0) is added to the N-terminal glycine residue of the α subunits of certain receptor-coupled guanine nucleotide-binding regulatory proteins (G proteins). The Ga subunit (GPA1 gene product) coupled to yeast pheromone receptors exists as a pool of both myristoylated and unmyristoylated species. After treatment of MATa cells with α factor, the myristoylated form of Gpa1p increases dramatically, and the unmyristoylated form decreases concomitantly. This pheromone-stimulated shift depends on the function of STE2 (α-factor receptor), STE11 (a protein kinase in the response pathway), and NMT1 (myristoyl-CoA:protein N-myristoyltransferase) genes and uses the existing pool of fatty acids (is not blocked by cerulenin). Myristoylated Gpa1p persists long after pheromone is removed. Because myristoylation is essential for proper Gα-Gβγ association and receptor coupling, pheromone-dependent stimulation of Gpa1p myristoylation may be an important contributing factor in adaptation after signal transmission.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - Oct 15 1993|
- Posttranslational modification
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