Sorbic acid triggers rapid formation of proteasome storage granules in Saccharomyces cerevisiae
Authors:Shoei Tanaka1, Mitsuki Imajo1, Mieko Hayashi2, Akira Matsuura2 and Shingo Izawa1
doi: 10.15698/mic2026.08.886
Volume 13, pp. 329 to 339, published 12/08/2026.
1 Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan. 2 Department of Biology, Graduate School of Science, Chiba University, Chiba 263-8522, Japan.
Keywords:
sorbic acid, acidification, proteasome, proteasome storage granules, proteolysis, UBA-UBL shuttle factors, Saccharomyces cerevisiae.
Corresponding Author(s):
Conflict of interest statement:
No potential conflicts of interest were reported by the authors.
Please cite this article as:
Shoei Tanaka, Mitsuki Imajo, Mieko Hayashi, Akira Matsuura, Shingo Izawa (2026). Sorbic acid triggers rapid formation of proteasome storage granules in Saccharomyces cerevisiae. Microbial Cell 13: 329-339. doi: 10.15698/mic2026.08.886
© 2026 Tanaka et al. This is an open-access article released under the terms of the Creative Commons Attribution (CC BY) license, which allows the unrestricted use, distribution, and reproduction in any medium, provided the original author and source are acknowledged.
Abstract:
Proteasomes are primarily located within the nuclei of proliferating cells; however, their localization changes dynamically in response to environmental conditions. Saccharomyces cerevisiae forms proteasome storage granules (PSGs) in the cytoplasm upon glucose depletion, mitochondrial stress, transition to quiescence, or acetic acid stress, with intracellular acidification acting as a key trigger. Despite possessing similar dissociation constants, sorbic acid and acetic acid are noted to exert different physiological effects on yeast cells. In this study, we demonstrate that sorbic acid induces the fastest PSG formation ever reported (within 30 min) at lower concentrations than acetic acid, accompanied by the inhibition of proteasomal proteolysis. Conversely, our analysis of the required factors revealed that, similar to acetic acid, the proteasome subunits Sem1 and Rpn13 are essential for sorbic acid-induced PSG formation. In contrast, the shuttle factors Dsk2 and Rad23, along with the E3 ubiquitin ligase Hul5—which are required for PSG formation under mitochondrial stress or quiescence—are dispensable for sorbic acid-induced PSG formation. These findings not only identify a novel condition for rapid PSG formation but also provide new insights into the physiological effects of sorbic acid on the proteasome, highlighting both its similarities to and differences from acetic acid.