The plant hormone auxin is perceived by the nuclear F-box protein TIR1 receptor family and regulates gene expression through degradation of Aux/IAA transcriptional repressors. Several studies have revealed the importance of the proteasome in auxin signalling, but details on how the proteolytic machinery is regulated and how this relates to degradation of Aux/IAA proteins remains unclear. Here we show that an Arabidopsis homologue of the proteasome inhibitor PI31, which we name PROTEASOME REGULATOR1 (PTRE1), is a positive regulator of the 26S proteasome. Loss-of-function ptre1 mutants are insensitive to auxin-mediated suppression of proteasome activity, show diminished auxin-induced degradation of Aux/IAA proteins and display auxin-related phenotypes. We found that auxin alters the subcellular localization of PTRE1, suggesting this may be part of the mechanism by which it reduces proteasome activity. Based on these results, we propose that auxin regulates proteasome activity via PTRE1 to fine-tune the homoeostasis of Aux/IAA repressor proteins thus modifying auxin activity.
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http://dx.doi.org/10.1038/ncomms11388 | DOI Listing |
Nat Commun
January 2025
Division of Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Chronic lymphocytic leukemia is a malignant lymphoproliferative disorder for which primary or acquired drug resistance represents a major challenge. To investigate the underlying molecular mechanisms, we generate a mouse model of ibrutinib resistance, in which, after initial treatment response, relapse under therapy occurrs with an aggressive outgrowth of malignant cells, resembling observations in patients. A comparative analysis of exome, transcriptome and proteome of sorted leukemic murine cells during treatment and after relapse suggests alterations in the proteasome activity as a driver of ibrutinib resistance.
View Article and Find Full Text PDFInt Immunopharmacol
January 2025
Department of Biotherapy, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041 Sichuan Province, People's Republic of China. Electronic address:
Chimeric antigen receptor T (CAR-T) cell therapy targeting B cell mature antigen (BCMA) has shown remarkable clinical benefits in treating multiple myeloma (MM). Bortezomib, a proteasome inhibitor approved as a first-line agent for MM for two decades, has demonstrated potent antitumor activity. In this study, we found that bortezomib treatment stabilizes the expression of BCMA and conceived the hypothesis that BCMA CAR-T therapy combined with bortezomib would enhance the anti-MM efficacy.
View Article and Find Full Text PDFPlants (Basel)
January 2025
Corteva Agriscience, 7000 NW 62nd Ave, Johnston, IA 50131, USA.
Maize lethal necrosis (MLN) is a significant threat to food security in Sub-Saharan Africa (SSA), with limited commercial inbred lines displaying tolerance. This study analyzed the transcriptomes of four commercially used maize inbred lines and a non-adapted inbred line, all with varying response levels to MLN. RNA-Seq revealed differentially expressed genes in response to infection by maize chlorotic mottle virus (MCMV) and sugarcane mosaic virus (SCMV), the causative agents of MLN.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Fisheries College, Hunan Agricultural University, Changsha 410128, China.
belongs to the NOD-like receptor family and is recognized as a modulator of innate immune mechanisms. In this study, we firstly report that () acts as a negative regulator in the antiviral immune response. is ubiquitously expressed across tested tissues, displaying particularly high expression in the intestine, spleen, gill and kidney.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu 611130, China.
As a crucial post-translational modification (PTM), protein ubiquitination mediates the breakdown of particular proteins, which plays a pivotal role in a large number of biological processes including plant growth, development, and stress response. The ubiquitin-proteasome system (UPS) consists of ubiquitin (Ub), ubiquitinase, deubiquitinating enzyme (DUB), and 26S proteasome mediates more than 80% of protein degradation for protein turnover in plants. For the ubiquitinases, including ubiquitin-activating enzyme (E1), ubiquitin-conjugating enzyme (E2), and ubiquitin ligase (E3), the FBK (F-box Kelch repeat protein) is an essential component of multi-subunit E3 ligase SCF (Skp1-Cullin 1-F-box) involved in the specific recognition of target proteins in the UPS.
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