Proteomic and Genomic Characterization of a Yeast Model for Ogden Syndrome

Abstract

Naa10 is a N α -terminal acetyltransferase that, in a complex with its auxiliary subunit Naa15, co-translationally acetylates the α-amino group of newly synthetized proteins as they emerge from the ribosome. Roughly 40-50% of the human proteome is acetylated by Naa10, rendering this an enzyme with one of the most broad substrate ranges known. Recently, we reported an X-linked disorder of infancy, Ogden syndrome, in two families harboring a c.109T>C (p.Ser37Pro) variant in NAA10. In the present study we performed in-depth characterization of a yeast model of Ogden syndrome. Stress tests and proteomic analyses suggest that the S37P mutation disrupts Naa10 function thereby reducing cellular fitness, possibly due to an impaired functionality of molecular chaperones, Hsp104, Hsp40 and the Hsp70 family. Microarray and RNA-seq revealed a pseudodiploid gene expression profile in ΔNaa10 cells, likely responsible for a mating defect. In conclusion, the data presented here further support the disruptive nature of the S37P/Ogden mutation and identify affected cellular processes potentially contributing to the severe phenotype seen in Ogden syndrome.

Loss of N-terminal acetyltransferase A activity induces thermally unstable ribosomal proteins and increases their turnover

“…Conversely, the turnover rates of mitochondrial ribosomal proteins showed a mixed behavior suggesting that an enhanced synthesis of mitochondrial ribosomal proteins is induced as a response of impaired mitochondrial function. This phenomenon has also been described in previous ribosome profiling and RNA-seq studies, which showed elevated translation of nuclear-encoded genes of mitochondrial ribosomal proteins in NatA-lacking strains ( 8, 54, 57 ).…”

Expanding the Phenotypic spectrum ofNAA10-related neurodevelopmental syndrome andNAA15-related neurodevelopmental syndrome

“…This discrepancy between the biochemical results for p.Arg83Cys missense in NAA10 from the reductionistic approach focusing on NatA enzymatic acetylation of a substrate peptide in a test tube compared to the phenotypic presentation in the humans with this same change can best be addressed in the future with patient-derived cell lines and/or animal models. An alternative has been to study the human mutations in the human genes expressed in a S. cerevisiae model knocked out for endogenous yeast Naa10 and/or Naa15 (Van Damme et al 2014; Max J. Dörfel et al 2017; H. Cheng et al 2018), although S. cerevisiae is a much simpler unicellular organism that does not represent the complexity of a human cell or a human being.…”

“…The identical variant was recently reported in a third family (Gogoll et al 2021). There is a S. cerevisiae model for the Naa10 Ser37Pro mutant, in which that variant impairs NatA complex formation and leads to a reduction in both NatA catalytic activity and functionality (Van Damme et al 2014; Max J. Dörfel et al 2017). Furthermore, OS patient-derived cells have impaired in vivo NTA of a few NatA substrates (Myklebust et al 2015).…”

Naa12compensates forNaa10in mice in the amino-terminal acetylation pathway

“…Among these, the X-linked Ogden syndrome (OS) (25,26) shows the most severe pathological features such as infant lethality and has reduced NatA catalytic activity. In a Saccharomyces cerevisiae model for the Naa10 Ser37Pro mutant, the mutation impairs NatA complex formation and leads to a reduction in NatA catalytic activity and functionality (27,28). Further, OS patient-derived cells have impaired NTA in vivo of some NatA substrates (25).…”