Seed longevity is controlled by metacaspases

• Published in: Nature communications Vol. 15; no. 1; pp. 6748 - 17
• Main Authors: Liu, Chen, Hatzianestis, Ioannis H, Pfirrmann, Thorsten, Reza, Salim H, Minina, Elena A, Moazzami, Ali, Stael, Simon, Gutierrez-Beltran, Emilio, Pitsili, Eugenia, Dörmann, Peter, D'Andrea, Sabine, Gevaert, Kris, Romero-Campero, Francisco, Ding, Pingtao, Nowack, Moritz K, Van Breusegem, Frank, Jones, Jonathan D G, Bozhkov, Peter V, Moschou, Panagiotis N
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 08.08.2024; Nature Portfolio
• Subjects: Adapters; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biochemistry and Molecular Biology; Biokemi och molekylärbiologi; Cell division; Cleavage; Desiccation; Droplets; Endoplasmic reticulum; Endoplasmic Reticulum - metabolism; Gene Expression Regulation, Plant; Homeostasis; Life Sciences; Life span; Lipid Droplets - metabolism; Lipids; Localization; Longevity; Longevity - genetics; Longevity - physiology; Mutants; Mutation; Protein folding; Proteins; Proteolysis; Proteostasis; Regulatory mechanisms (biology); Seeds; Seeds - metabolism; Storage proteins; Ubiquitination; Valosin Containing Protein - genetics; Valosin Containing Protein - metabolism
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-50848-2

To survive extreme desiccation, seeds enter a period of quiescence that can last millennia. Seed quiescence involves the accumulation of protective storage proteins and lipids through unknown adjustments in protein homeostasis (proteostasis). Here, we show that mutation of all six type-II metacaspase (MCA-II) proteases in Arabidopsis thaliana disturbs proteostasis in seeds. MCA-II mutant seeds fail to restrict the AAA ATPase CELL DIVISION CYCLE 48 (CDC48) at the endoplasmic reticulum to discard misfolded proteins, compromising seed storability. Endoplasmic reticulum (ER) localization of CDC48 relies on the MCA-IIs-dependent cleavage of PUX10 (ubiquitination regulatory X domain-containing 10), the adaptor protein responsible for titrating CDC48 to lipid droplets. PUX10 cleavage enables the shuttling of CDC48 between lipid droplets and the ER, providing an important regulatory mechanism sustaining spatiotemporal proteolysis, lipid droplet dynamics, and protein homeostasis. In turn, the removal of the PUX10 adaptor in MCA-II mutant seeds partially restores proteostasis, CDC48 localization, and lipid droplet dynamics prolonging seed lifespan. Taken together, we uncover a proteolytic module conferring seed longevity.