Urmylation and tRNA thiolation functions of ubiquitin-like Uba4·Urm1 systems are conserved from yeast to man

• Published in: FEBS letters Vol. 589; no. 8; pp. 904 - 909
• Main Authors: Jüdes, André, Ebert, Folke, Bär, Christian, Thüring, Kathrin L., Harrer, Aileen, Klassen, Roland, Helm, Mark, Stark, Michael J.R., Schaffrath, Raffael
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 02.04.2015
• Subjects: Anticodon - metabolism; Conserved Sequence; HeLa Cells; Humans; Nucleotidyltransferases - chemistry; Nucleotidyltransferases - metabolism; RNA, Transfer - genetics; RNA, Transfer - metabolism; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - metabolism; Sequence Homology, Amino Acid; Sulfurtransferases - chemistry; Sulfurtransferases - metabolism; tRNA thiolation; Uba4 (hUBA4/MOCS3); Ubiquitin-like urmylation; Ubiquitins - chemistry; Ubiquitins - metabolism; Urm1 (hURM1); tRNA thiolation; Urm1 (hURM1); Ubiquitin-like urmylation; Saccharomyces cerevisiae; Uba4 (hUBA4/MOCS3)
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2015.02.024

•Yeast gene shuffles reveal eukaryal ubiquitin-like Urm1·Uba4 systems are conserved.•Conservation is at the level of both protein urmylation and tRNA anticodon thiolation.•Uba4, the E1-like Urm1 activator, is identified as a novel urmylation target in yeast.•Human URM1 conjugates to Ahp1, a bona fide target for protein urmylation in yeast.•Additional urmylation targets are likely shared between yeast and human cells. The ubiquitin-like protein Urm1 from budding yeast and its E1-like activator Uba4 have dual roles in protein urmylation and tRNA thiolation pathways. To study whether these are conserved among eukaryotes, we used gene shuffles to replace the yeast proteins by their human counterparts, hURM1 and hUBA4/MOCS3. As judged from biochemical and genetical assays, hURM1 and hUBA4 are functional in yeast, albeit at reduced efficiencies. They mediate urmylation of the peroxiredoxin Ahp1, a known urmylation target in yeast, and support tRNA thiolation. Similar to hUBA4, yeast Uba4 itself is modified by Urm1 and hURM1 suggesting target overlap between eukaryal urmylation pathways. In sum, our study shows that dual-function ubiquitin-like Urm1·Uba4 systems are conserved and exchangeable between human and yeast cells.