SUMMARY PARAGRAPH for NAT1
Nat1p is part of an N-terminal acetyl transferase; it acts in a complex with Ard1p to catalyze the cotranslational N-terminal acetylation of many yeast proteins (4, 1). Three N-terminal acetyl transferases have been identified in yeast: Nat1p/Ard1p, Nat3p, and Mak3p (7). These enzymes are responsible for the N-terminal modification of more than half of yeast proteins (7). Nat1p/Ard1p transfers an acetyl group from acetyl coenzyme A to the alpha-amino group of Ser, Ala, Gly, or Thr N-terminal residues (7, 8).
Deletion of NAT1 causes slow growth, failure to enter stationary phase, and defects in sporulation (1, 8). Cells lacking Nat1p or Ard1p show derepression of silent mating type loci; overexpression of Sir1p, a silent information regulator, can suppress this derepression phenotype (1, 9). NAT1 is also a modifier of position effect at telomeres; in nat1 mutants transcriptional repression is no longer seen near telomeres 10. Overexpression or deletion of NAT1 can lead to chromosomal instability (11). These mutant phenotypes suggest that the Nat1p/Ard1p complex may modify proteins important for chromatin structure and function.
Last updated: 1999-12-31