The intrinsic chaperone network of Arabidopsis stem cells confers protection against proteotoxic stress

• Published in: Aging cell Vol. 20; no. 8; pp. e13446 - n/a
• Main Authors: Llamas, Ernesto, Torres‐Montilla, Salvador, Lee, Hyun Ju, Barja, María Victoria, Schlimgen, Elena, Dunken, Nick, Wagle, Prerana, Werr, Wolfgang, Zuccaro, Alga, Rodríguez‐Concepción, Manuel, Vilchez, David
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.08.2021; John Wiley and Sons Inc
• Subjects: Arabidopsis; Cell Differentiation; chaperones; Climate change; Environmental conditions; Experiments; heat stress; Homeostasis; Molecular Chaperones - genetics; Original; Plant breeding; Plant cells; plant stem cells; Proteasomes; Protein Aggregates - genetics; protein aggregation; Protein interaction; protein misfolding; Proteins; Proteomes; proteostasis; Proteostasis - genetics; Stem cells; Stem Cells - metabolism; heat stress; proteostasis; chaperones; plant stem cells; protein aggregation; protein misfolding
• ISSN: 1474-9718; 1474-9726; 1474-9726
• DOI: 10.1111/acel.13446

The biological purpose of plant stem cells is to maintain themselves while providing new pools of differentiated cells that form organs and rejuvenate or replace damaged tissues. Protein homeostasis or proteostasis is required for cell function and viability. However, the link between proteostasis and plant stem cell identity remains unknown. In contrast to their differentiated counterparts, we find that root stem cells can prevent the accumulation of aggregated proteins even under proteotoxic stress conditions such as heat stress or proteasome inhibition. Notably, root stem cells exhibit enhanced expression of distinct chaperones that maintain proteome integrity. Particularly, intrinsic high levels of the T‐complex protein‐1 ring complex/chaperonin containing TCP1 (TRiC/CCT) complex determine stem cell maintenance and their remarkable ability to suppress protein aggregation. Overexpression of CCT8, a key activator of TRiC/CCT assembly, is sufficient to ameliorate protein aggregation in differentiated cells and confer resistance to proteotoxic stress in plants. Taken together, our results indicate that enhanced proteostasis mechanisms in stem cells could be an important requirement for plants to persist under extreme environmental conditions and reach extreme long ages. Thus, proteostasis of stem cells can provide insights to design and breed plants tolerant to environmental challenges caused by the climate change. Plant stem cells provide new pools of differentiated cells to replace damaged tissues. We find that root stem cells prevent protein aggregation even under proteotoxic stress through their upregulated basal high expression of distinct chaperones. By mimicking this proteostasis network in other cells, we increased resistance to heat stress in plants. Together, our findings indicate that enhanced proteostasis in stem cells could allow plants to persist under extreme environmental conditions.