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Research Project
Discovery and functional significance of post-translational N-terminal acetylation
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N-terminal acetylation shields proteins from degradation and promotes age-dependent motility and longevity
Publication . Varland, Sylvia; Silva, Rui Duarte; Kjosås, Ine; Faustino, Alexandra; Bogaert, Annelies; Billmann, Maximilian; Boukhatmi, Hadi; Kellen, Barbara; Costanzo, Michael; Drazic, Adrian; Osberg, Camilla; Chan, Katherine; Zhang, Xiang; Tong, Amy Hin Yan; Andreazza, Simonetta; Lee, Juliette J.; Nedyalkova, Lyudmila; Ušaj, Matej; Whitworth, Alexander J.; Andrews, Brenda J.; Moffat, Jason; Myers, Chad L.; Gevaert, Kris; Boone, Charles; Martinho, Rui Gonçalo; Arnesen, Thomas
Most eukaryotic proteins are N-terminally acetylated, but the functional impact on a global scale has remained obscure. Using genome-wide CRISPR knockout screens in human cells, we reveal a strong genetic dependency between a major N-terminal acetyltransferase and specific ubiquitin ligases. Biochemical analyses uncover that both the ubiquitin ligase complex UBR4-KCMF1 and the acetyltransferase NatC recognize proteins bearing an unacetylated N-terminal methionine followed by a hydrophobic residue. NatC KO-induced protein degradation and phenotypes are reversed by UBR knockdown, demonstrating the central cellular role of this interplay. We reveal that loss of Drosophila NatC is associated with male sterility, reduced longevity, and age-dependent loss of motility due to developmental muscle defects. Remarkably, muscle-specific overexpression of UbcE2M, one of the proteins targeted for NatC KO-mediated degradation, suppresses defects of NatC deletion. In conclusion, NatC-mediated N-terminal acetylation acts as a protective mechanism against protein degradation, which is relevant for increased longevity and motility.
The most common protein modification in eukaryotes is N-terminal acetylation, but its functional impact has remained enigmatic. Here, the authors find that a key role for N-terminal acetylation is shielding proteins from ubiquitin ligase-mediated degradation, mediating motility and longevity.
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Funding agency
European Commission
Funding programme
H2020
Funding Award Number
772039