Kha The Nguyen Ju, Shinyeong Kim, Sang-Yoon Lee, Chang-Seok Lee, Cheolju Hwang, Cheol-Sang 2024-01-19T12:32:08Z 2024-01-19T12:32:08Z 2022-04-05 2022-03 1016-8478 https://pubs.kist.re.kr/handle/201004/115567 Ubiquitin (Ub) is post-translationally modified by Ub itself or Ub-like proteins, phosphorylation, and acetylation, among others, which elicits a variety of Ub topologies and cellular functions. However, N-terminal (Nt) modifications of Ub remain unknown, except the linear head-to-tail ubiquitylation via Nt-Met. Here, using the yeast Saccharomyces cerevisiae and an Nt-arginylated Ub-specific antibody, we found that the detectable level of Ub undergoes Nt-Met excision, Nt-deamination, and Nt-arginylation. The resulting Ntarginylated Ub and its conjugated proteins are upregulated in the stationary-growth phase or by oxidative stress. We further proved the existence of Nt-arginylated Ub in vivo and identified Nt-arginylated Ub-protein conjugates using stable isotope labeling by amino acids in cell culture (SILAC)-based tandem mass spectrometry. In silico structural modeling of Nt-arginylated Ub predicted that Nt-Arg flexibly protrudes from the surface of the Ub, thereby most likely providing a docking site for the factors that recognize it. Collectively, these results reveal unprecedented Nt-arginylated Ub and the pathway by which it is produced, which greatly expands the known complexity of the Ub code. English 한국분자세포생물학회 N-Terminal Modifications of Ubiquitin via Methionine Excision, Deamination, and Arginylation Expand the Ubiquitin Code Article 10.14348/molcells.2022.2027 1 Molecules and Cells, v.45, no.3, pp.158 - 167 Molecules and Cells 45 3 158 167 Y scie scopus kci ART002828397 000766610300001 2-s2.0-85126490401 Biochemistry & Molecular Biology Cell Biology Biochemistry & Molecular Biology Cell Biology Article; Early Access CELLULAR-PROTEINS END ACETYLATION SYSTEM arginylation deamination methionine excision N-degron proteolysis ubiquitin code