Urm1: A Non-Canonical UBL

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...

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Main Authors: Martin Termathe, Sebastian A. Leidel
Format: Article
Language:English
Published: MDPI AG 2021-01-01
Series:Biomolecules
Subjects:
Online Access:https://www.mdpi.com/2218-273X/11/2/139
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author Martin Termathe
Sebastian A. Leidel
author_facet Martin Termathe
Sebastian A. Leidel
author_sort Martin Termathe
collection DOAJ
description 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 (mcm<sup>5</sup>s<sup>2</sup>U), 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.
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spelling doaj.art-79fb53bacc2d4751ab0245d139b8e9bf2023-12-03T14:14:22ZengMDPI AGBiomolecules2218-273X2021-01-0111213910.3390/biom11020139Urm1: A Non-Canonical UBLMartin Termathe0Sebastian A. Leidel1Institute of Biochemistry, Protein Biochemistry and Photobiocatalysis, University of Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, GermanyDepartment of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, SwitzerlandUrm1 (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 (mcm<sup>5</sup>s<sup>2</sup>U), 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.https://www.mdpi.com/2218-273X/11/2/1392-thiolationtRNA modificationthiocarboxylaterhodanesesulfur-carrier proteinnon-canonical UBL
spellingShingle Martin Termathe
Sebastian A. Leidel
Urm1: A Non-Canonical UBL
Biomolecules
2-thiolation
tRNA modification
thiocarboxylate
rhodanese
sulfur-carrier protein
non-canonical UBL
title Urm1: A Non-Canonical UBL
title_full Urm1: A Non-Canonical UBL
title_fullStr Urm1: A Non-Canonical UBL
title_full_unstemmed Urm1: A Non-Canonical UBL
title_short Urm1: A Non-Canonical UBL
title_sort urm1 a non canonical ubl
topic 2-thiolation
tRNA modification
thiocarboxylate
rhodanese
sulfur-carrier protein
non-canonical UBL
url https://www.mdpi.com/2218-273X/11/2/139
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AT sebastianaleidel urm1anoncanonicalubl