Global impacts of peroxisome and pexophagy dysfunction revealed through multi-omics analyses of lon2 and atg2 mutants.

Peroxisomes house diverse metabolic pathways that are essential for plant and animal survival, including enzymes that produce or inactivate toxic byproducts. Despite the importance of peroxisomes and their collaborations with other organelles, the mechanisms that trigger or prevent peroxisome turnover and the cellular impacts of impaired peroxisomes are incompletely understood. When Arabidopsis thaliana LON2, a peroxisomal protein with chaperone and protease capacity, is disrupted, metabolic dysfunction and protein instability in peroxisomes ensue.

Hormonal control of underwater germination in rice.

The ability to germinate, develop, and thrive underwater is key to efficient rice cultivation. In this issue of Developmental Cell, Wang et al. (2024) illuminate a hormone synthesis and inactivation cascade that promotes germination of submerged rice seeds and may allow improved germination in the field.

The ubiquitin-protein ligase MIEL1 localizes to peroxisomes to promote seedling oleosin degradation and lipid droplet mobilization.

Lipid droplets are organelles conserved across eukaryotes that store and release neutral lipids to regulate energy homeostasis. In oilseed plants, fats stored in seed lipid droplets provide fixed carbon for seedling growth before photosynthesis begins. As fatty acids released from lipid droplet triacylglycerol are catabolized in peroxisomes, lipid droplet coat proteins are ubiquitinated, extracted, and degraded.

An Arabidopsis pre-RNA processing8a (prp8a) missense allele restores splicing of a subset of mis-spliced mRNAs.

Eukaryotic precursor mRNAs often harbor noncoding introns that must be removed prior to translation. Accurate splicing of precursor messenger RNA depends on placement and assembly of small nuclear ribonucleoprotein (snRNP) sub-complexes of the spliceosome. Yeast (Saccharomyces cerevisiae) studies established a role in splice-site selection for PRE-RNA PROCESSING8 (PRP8), a conserved spliceosome scaffolding protein of the U5 snRNP.

Plant peroxisome proteostasis-establishing, renovating, and dismantling the peroxisomal proteome.

Plant peroxisomes host critical metabolic reactions and insulate the rest of the cell from reactive byproducts. The specialization of peroxisomal reactions is rooted in how the organelle modulates its proteome to be suitable for the tissue, environment, and developmental stage of the organism. The story of plant peroxisomal proteostasis begins with transcriptional regulation of peroxisomal protein genes and the synthesis, trafficking, import, and folding of peroxisomal proteins.