Hydroxylation of the Acetyltransferase NAA10 Trp38 Is Not an Enzyme-Switch in Human Cells

Rasmus Ree,Karoline Krogstad,Thomas Arnesen,Magnus E Jakobsson,Nina Mctiernan

doi:10.3390/ijms222111805

Abstract

NAA10 is a major N-terminal acetyltransferase (NAT) that catalyzes the cotranslational N-terminal (Nt-) acetylation of 40% of the human proteome. Several reports of lysine acetyltransferase (KAT) activity by NAA10 exist, but others have not been able to find any NAA10-derived KAT activity, the latter of which is supported by structural studies. The KAT activity of NAA10 towards hypoxia-inducible factor 1α (HIF-1α) was recently found to depend on the hydroxylation at Trp38 of NAA10 by factor inhibiting HIF-1α (FIH). In contrast, we could not detect hydroxylation of Trp38 of NAA10 in several human cell lines and found no evidence that NAA10 interacts with or is regulated by FIH. Our data suggest that NAA10 Trp38 hydroxylation is not a switch in human cells and that it alters its catalytic activity from a NAT to a KAT.

Highlights

Protein N-terminal acetylation (Nt-acetylation) is pervasive and highly conserved among eukaryotes
One of the samples was prepared by NAA10-V5 immunoprecipitation (IP) in HEK293 cells and further fractionation off-line prior to liquid chromatography coupled mass spectrometry (LC/MS) to obtain comprehensive
We only identified the missed cleavage peptide (30)YYFYHGLSWPQLSYIAEDENGKIVGYVLAK(59) in the fractionated sample; this peptide was likewise not hydroxylated on Trp38

Summary

Introduction

Protein N-terminal acetylation (Nt-acetylation) is pervasive and highly conserved among eukaryotes. A functional effect of Nt-acetylation on a substrate protein has been described for a modest number of substrates. They have been termed NatA-NatF and NatH and have catalytic subunits NAA10-NAA60 and NAA80 [1]. The catalytic subunits bind acetylcoenzyme A (Ac-CoA) and catalyze the transfer of an acetyl group from Ac-CoA to the N-terminal amino group of the protein substrate. NatF, which is localized to the Golgi apparatus and facesthe cytosol [30,31], and NatH, the actin NAT [32,33,34,35,36], are not ribosome-bound and have posttranslational activities

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