title: Microscopy-based Saccharomyces cerevisiae complementation model reveals functional conservation and redundancy of N-terminal acetyltransferases.
abstract: N-terminal acetylation is a highly abundant protein modification catalyzed by N-terminal acetyltransferases (NATs) NatA-NatG. The Saccharomyces cerevisiae protein Arl3 depends on interaction with Sys1 for its localization to the Golgi and this targeting strictly requires NatC-mediated N-terminal acetylation of Arl3. We utilized the Arl3 acetylation-dependent localization phenotype as a model system for assessing the functional conservation and in vivo redundancy of several human NATs. The catalytic subunit of human NatC, hNaa30 (Mak3), restored Arl3 localization in the absence of yNaa30, but only in the presence of either yeast or human Naa35 subunit (Mak10). In contrast, hNaa35 was not able to replace its yeast orthologue without the co-expression of hNaa30, suggesting co-evolution of the two NatC subunits. The most recently discovered and organellar human NAT, NatF/Naa60, restored the Golgi localization of Arl3 in the absence of yNaa30. Interestingly, this was also true for hNaa60 lacking its membrane-binding domain whereas hNaa50 did not complement NatC function. This in vivo redundancy reflects NatC and NatF´s overlapping in vitro substrate specificities. The yeast model presented here provides a robust and rapid readout of NatC and NatF activity in vivo, and revealed evolutionary conservation of the NatC complex and redundancy between NatC and NatF.
authors.affiliation: Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.|Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway.
authors.forename: Camilla
authors.initials: C
authors.lastname: Osberg
authors.affiliation: Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.
authors.forename: Henriette
authors.initials: H
authors.lastname: Aksnes
authors.affiliation: Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.
authors.forename: Sandra
authors.initials: S
authors.lastname: Ninzima
authors.affiliation: Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.
authors.forename: Michaël
authors.initials: M
authors.lastname: Marie
authors.affiliation: Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.|Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway.
authors.forename: Thomas
authors.initials: T
authors.lastname: Arnesen
mesh_terms: D020727:ADP-Ribosylation Factors / Q000378:metabolism; D000107:Acetylation; D005816:Genetic Complementation Test; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D063206:N-Terminal Acetyltransferases / Q000502:physiology*; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D063206:N-Terminal Acetyltransferases; D020727:ADP-Ribosylation Factors; C490249:ARL3 protein, S cerevisiae