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Mmi1, the Yeast Homologue of Mammalian TCTP, Associates with Stress Granules in Heat-Shocked Cells and Modulates Proteasome Activity
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SYSNO ASEP 0422075 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Mmi1, the Yeast Homologue of Mammalian TCTP, Associates with Stress Granules in Heat-Shocked Cells and Modulates Proteasome Activity Author(s) Rinnerthaler, M. (AT)
Lejsková, Renata (MBU-M) RID
Groušl, Tomáš (MBU-M) RID, ORCID
Strádalová, Vendula (UEM-P) RID
Heeren, G. (AT)
Richter, K. (AT)
Breitenbach-Koller, L. (AT)
Malínský, Jan (UEM-P) RID, ORCID
Hašek, Jiří (MBU-M) RID, ORCID
Breitenbach, M. (AT)Source Title PLoS ONE. - : Public Library of Science - ISSN 1932-6203
Roč. 8, č. 10 (2013)Number of pages 13 s. Language eng - English Country US - United States Keywords CONTROLLED TUMOR PROTEIN ; SACCHAROMYCES-CEREVISIAE ; OXIDATIVE STRESS Subject RIV EE - Microbiology, Virology Subject RIV - cooperation Institute of Experimental Medicine - Genetics ; Molecular Biology R&D Projects GAP305/12/0480 GA ČR - Czech Science Foundation (CSF) GAP302/11/0146 GA ČR - Czech Science Foundation (CSF) 7AMB12AT002 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support MBU-M - RVO:61388971 ; UEM-P - RVO:68378041 UT WOS 000326241200040 DOI 10.1371/journal.pone.0077791 Annotation As we have shown previously, yeast Mmi1 protein translocates from the cytoplasm to the outer surface of mitochondria when vegetatively growing yeast cells are exposed to oxidative stress. Here we analyzed the effect of heat stress on Mmi1 distribution. We performed domain analyses and found that binding of Mmi1 to mitochondria is mediated by its central alpha-helical domain (V-domain) under all conditions tested. In contrast, the isolated N-terminal flexible loop domain of the protein always displays nuclear localization. Using immunoelectron microscopy we confirmed re-location of Mmi1 to the nucleus and showed association of Mmi1 with intact and heat shock-altered mitochondria. We also show here that mmi1 Delta mutant strains are resistant to robust heat shock with respect to clonogenicity of the cells. To elucidate this phenotype we found that the cytosolic Mmi1 holoprotein re-localized to the nucleus even in cells heat-shocked at 40 degrees C. Upon robust heat shock at 46 degrees C, Mmi1 partly co-localized with the proteasome marker Rpn1 in the nuclear region as well as with the cytoplasmic stress granules defined by Rpg1 (eIF3a). We co-localized Mmi1 also with Bre5, Ubp3 and Cdc48 which are involved in the protein de-ubiquitination machinery, protecting protein substrates from proteasomal degradation. A comparison of proteolytic activities of wild type and mmi1 Delta cells revealed that Mmi1 appears to be an inhibitor of the proteasome. We conclude that one of the physiological functions of the multifunctional protein module, Mmi1, is likely in regulating degradation and/or protection of proteins thereby indirectly regulating the pathways leading to cell death in stressed cells Workplace Institute of Microbiology Contact Eliška Spurná, eliska.spurna@biomed.cas.cz, Tel.: 241 062 231 Year of Publishing 2014
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