N alpha-acetyltransferase deficiency alters protein synthesis in Saccharomyces cerevisiae

Acetylation is the most frequently occurring chemical modification of the alpha-NH2 group of eukaryotic proteins and is catalyzed by a N alpha-acetyltransferase. Two-dimensional gel electrophoresis was used to compare the soluble proteins synthesized in wild type and a mutant (aaa1) yeast cells lacking N alpha-acetyltransferase. Among 855 soluble proteins identified in wild type and mutant, approximately 20% of the proteins in the mutant either disappeared or were shifted to higher pI without a change of molecular mass, and 27 proteins were observed only in the mutant. In addition, the synthesis of another 12% of the proteins in the mutant was either diminished or enhanced, suggesting that the acetylation of certain regulatory proteins may affect their expression. This is the first demonstration of the broad-based functional role of N alpha-acetylation in eukaryotic protein synthesis.