Urm1 protects proteins in stress situations

In response to stress Urm1 increases in cells. Urm1 self-interacts and associates with other proteins in co-operation with Uba4, forming a complex protein interaction network that results in the formation of a biomolecular condensate.
Illustration adapted from the original publication: https://doi.org/10.1016/j.cell.2024.06.009

To prevent proteins from being damaged during cellular stress, they are concentrated in so-called stress granules. Scientists from the department of Cellular Biochemistry at the Max Planck Institute of Biochemistry have now been able to show for the first time that the protein Urm1 has a critical role in this process. In yeast cells, the ubiquitin-like protein facilitates the onset of phase separation and thus the formation of stress granules. The results of the study were published in the scientific journal Cell.

Cellular Stress

Cells may experience various conditions of stress, such as heat stress during a fever. Such conditions can damage proteins – the molecules responsible for almost every process of life. The ability of cells to mount a defensive stress response is crucial for their survival.

As part of this response, the small protein ubiquitin is attached to damaged proteins to signal that they should be removed by degradation. Other proteins, however, must be protected during stress by concentrating them in so-called stress granules, via a process called phase separation. How this works exactly is not yet well understood. In a recent study, Lucas Cairo, Sae-Hun Park and their colleagues describe the role of the small protein Urm1 in regulating formation of reversible condensates under stress.

Urm1 Protein

Urm1 is related to ubiquitin and like ubiquitin can be covalently attached to target proteins. However, unlike ubiquitin, the cellular role of Urm1 had not been fully understood. The researchers found that stress triggers the covalent attachment of Urm1 to target substrates, promoting their assembly into stress granules and other biomolecular condensates. This enables their safe storage until the stress subsides.

More specifically, Urm1 facilitates the initiation of phase separation by enhancing protein-protein interactions conducive to this biophysical process. Key to this is the intrinsic ability of Urm1 to sense acidification of the cellular milieu that occurs upon stress. As a result, Urm1 self-interacts and associates with other proteins through multivalent interactions, forming a complex protein interaction network.

This network facilitates the deposition of proteins within condensates located in both the cytoplasm and cell nucleus. Attachment of Urm1 to target proteins is facilitated by the enzyme Uba4, which coassembles with Urm1 in the condensates. In the absence of Urm1, cells can no longer cope with stress. These findings identify Urm1 as a ubiquitin-like protein with a critical function in the cellular stress response.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Franz-Ulrich Hartl
Department of Cellular Biochemistry
Max Planck Institute of Biochemistry
Am Klopferspitz 18
82152 Martinsried

office-hartl@biochem.mpg.de
https://www.biochem.mpg.de/hartl

Originalpublikation:

Lucas V. Cairo, Xiaoyu Hong, Martin B.D. Müller, Patricia Yuste-Checa, Chandhuru Jagadeesan, Andreas Bracher, Sae-Hun Park, Manajit Hayer-Hartl and F.-Ulrich Hartl: Stress Dependent Condensate Formation Regulated by the Ubiquitin Related Modifier Urm1, Cell, June 2024
DOI: https://doi.org/10.1016/j.cell.2024.06.009

Weitere Informationen:

https://www.biochem.mpg.de/urm1-protects-proteins-in-stress-situations Press Release on the Website of the MPIB

Media Contact

Dr. Christiane Menzfeld Öffentlichkeitsarbeit
Max-Planck-Institut für Biochemie

All latest news from the category: Life Sciences and Chemistry

Articles and reports from the Life Sciences and chemistry area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Back to home

Comments (0)

Write a comment

Newest articles

Milestone 10-GeV experiment shines light on laser-plasma interactions

With dual lasers and an advanced gas injector system, researchers at the Berkeley Lab Laser Accelerator Center accelerated a high-quality beam of electrons to 10 billion electronvolts in just 30…

Universal barcodes unlock fast-paced small molecule synthesis

The development of molecules to study and treat disease is becoming increasingly burdened by the time and specificity required to analyze the vast amounts of data generated by synthesizing large…

Minuscule robots for targeted drug delivery

In the future, delivering therapeutic drugs exactly where they are needed within the body could be the task of miniature robots. Not little metal humanoid or even bio-mimicking robots; think…