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Research article2024Peer reviewedOpen access

Seed longevity is controlled by metacaspases

Liu, Chen; Hatzianestis, Ioannis H.; Pfirrmann, Thorsten; Reza, Salim H.; Minina, Elena A.; Moazzami, Ali; Stael, Simon; Gutierrez-Beltran, Emilio; Pitsili, Eugenia; Doermann, 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.

Abstract

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.Here, the authors have generated a metacapase type II depletion model providing evidence for their paramount role in seed longevity. They also show that this is accomplished by regulating the ERAD, the proteostatic pathway crucial for seeds.

Published in

Nature Communications
2024, Volume: 15, number: 1, article number: 6748Publisher: NATURE PORTFOLIO