An organellar nα-acetyltransferase, naa60, acetylates cytosolic N termini of transmembrane proteins and maintains Golgi integrity.
N-terminal acetylation is a major and vital protein modification catalyzed by N-terminal acetyltransferases (NATs). NatF, or Nα-acetyltransferase 60 (Naa60), was recently identified as a NAT in multicellular eukaryotes. Here, we find that Naa60 differs from all other known NATs by its Golgi localization. A new membrane topology assay named PROMPT and a selective membrane permeabilization assay established that Naa60 faces the cytosolic side of intracellular membranes. An Nt-acetylome analysis of NAA60-knockdown cells revealed that Naa60, as opposed to other NATs, specifically acetylates transmembrane proteins and has a preference for N termini facing the cytosol. Moreover, NAA60 knockdown causes Golgi fragmentation, indicating an important role in the maintenance of the Golgi's structural integrity. This work identifies a NAT associated with membranous compartments and establishes N-terminal acetylation as a common modification among transmembrane proteins, a thus-far poorly characterized part of the N-terminal acetylome.
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Henriette
H
Aksnes
Department of Medical Protein Research, VIB, 9000 Ghent, Belgium; Department of Biochemistry, Ghent University, 9000 Ghent, Belgium.
Petra
P
Van Damme
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Marianne
M
Goris
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Kristian K
KK
Starheim
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Michaël
M
Marie
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Svein Isungset
SI
Støve
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Camilla
C
Hoel
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Thomas Vikestad
TV
Kalvik
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway; Department of Clinical Science, University of Bergen, 5020 Bergen, Norway.
Kristine
K
Hole
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway; Department of Clinical Science, University of Bergen, 5020 Bergen, Norway.
Nina
N
Glomnes
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Clemens
C
Furnes
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Sonja
S
Ljostveit
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Mathias
M
Ziegler
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway.
Marc
M
Niere
Department of Medical Protein Research, VIB, 9000 Ghent, Belgium; Department of Biochemistry, Ghent University, 9000 Ghent, Belgium.
Kris
K
Gevaert
Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway; Department of Surgery, Haukeland University Hospital, 5021 Bergen, Norway. Electronic address: thomas.arnesen@mbi.uib.no.
Thomas
T
Arnesen
D000107:Acetylation; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism* / Q000473:pathology; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D063214:N-Terminal Acetyltransferase F / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D013379:Substrate Specificity
D008565:Membrane Proteins; C570958:NAA60 protein, human; D034741:RNA, Small Interfering; D063214:N-Terminal Acetyltransferase F