Urm1: A Non-Canonical UBL

Termathe, Martin; Leidel, Sebastian A. (2021). Urm1: A Non-Canonical UBL. Biomolecules, 11(2), p. 139. MDPI 10.3390/biom11020139

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Urm1 (ubiquitin related modifier 1) is a molecular fossil in the class of ubiquitin-like proteins (UBLs). It encompasses characteristics of classical UBLs, such as ubiquitin or SUMO (small ubiquitin-related modifier), but also of bacterial sulfur-carrier proteins (SCP). Since its main function is to modify tRNA, Urm1 acts in a non-canonical manner. Uba4, the activating enzyme of Urm1, contains two domains: a classical E1-like domain (AD), which activates Urm1, and a rhodanese homology domain (RHD). This sulfurtransferase domain catalyzes the formation of a C-terminal thiocarboxylate on Urm1. Thiocarboxylated Urm1 is the sulfur donor for 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U), a chemical nucleotide modification at the wobble position in tRNA. This thio-modification is conserved in all domains of life and optimizes translation. The absence of Urm1 increases stress sensitivity in yeast triggered by defects in protein homeostasis, a hallmark of neurological defects in higher organisms. In contrast, elevated levels of tRNA modifying enzymes promote the appearance of certain types of cancer and the formation of metastasis. Here, we summarize recent findings on the unique features that place Urm1 at the intersection of UBL and SCP and make Urm1 an excellent model for studying the evolution of protein conjugation and sulfur-carrier systems.

Item Type:

Journal Article (Review Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Leidel, Sebastian Andreas

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

2218-273X

Publisher:

MDPI

Language:

English

Submitter:

Christina Schüpbach

Date Deposited:

29 Jan 2021 14:33

Last Modified:

29 Jan 2021 14:33

Publisher DOI:

10.3390/biom11020139

PubMed ID:

33499055

BORIS DOI:

10.48350/151551

URI:

https://boris.unibe.ch/id/eprint/151551

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