“…In eukaryotes, cotranslational N-terminal Met excision (NME) by Met aminopeptidases (MetAP) and N-aterminal acetylation (Nt-acetylation) catalyzed by N-terminal acetyltransferases (Nats) are two major protein modifications contributing to the diversity of protein N termini and to the N-end rule (Giglione et al, 2000(Giglione et al, , 2003Ross et al, 2005;Frottin et al, 2009;Gibbs et al, 2014a). Although limited studies have been conducted in plants on the N-end rule (Giglione et al, 2003;Graciet et al, 2009;Holman et al, 2009;Adam et al, 2011;Bienvenut et al, 2011;Gibbs et al, 2011Gibbs et al, , 2014bLicausi et al, 2011;Weits et al, 2014), recent genomic and N-terminal acetylome analyses in yeast, animals, and plants revealed that the NME and Nt-acetylation processes, along with the related enzymatic activities, are largely conserved through eukaryotic lineages (Polevoda et al, 1999;Arnesen et al, 2009;Goetze et al, 2009;Bienvenut et al, 2012;Liu et al, 2013). Particularly, in vivo and in vitro studies have shown that all MetAPs share similar substrate specificity, removing the first Met only when the second residue has a small radius of gyration of the side chain; on the contrary, bulky amino acids do not allow the removal of the first Met (Bienvenut et al, 2012).…”