Proteomic Insights into Rice Protein Palmitoylation and Its Role in Cytosolic Translation
Protein palmitoylation, also known as S-acylation, is a reversible post-translational modification in which fatty acid group are covalently attached to cysteine residues via thioester bonds. To date, protein palmitoylation has been extensively studied in animal cells, where it plays critical roles in regulating cell signaling, energy metabolism, innate immunity, and cancer. Similarly, research in plants has demonstrated that palmitoylation contributes to the regulation of growth and development, adaptation to abiotic stress, and plant immunity. These findings suggest that palmitoylation is an evolutionary conserved modification with significant functional importance in both animal and plant cells. Despite progress in understanding palmitoylation in plants, research in this area remains relatively limited. A recent study in Arabidopsis revealed that over a thousand proteins undergo palmitoylation, highlighting its significant role in plants. However, this number may be an underestimate. According to the SwissPalm database, which catalogs palmitoylated proteins, more than 7,000 mammalian proteins are likely modified by palmitoylation. Furthermore, proteome-wide studies of palmitoylation in crop species are lacking, which limits our understanding of its functional roles in agriculturally important plants. To bridge this gap, we selected the monocot model plant Oryza sativa (rice) to conduct a global analysis of protein palmitoylation under basal conditions. By using the latest techniques, we obtained >6000 palmitoylated proteins from rice, significantly expanding the known repertoire of plant palmitoylated proteins. Additionally, we quantified the extent of palmitoylation in response to cold stress and explored the novel role of palmitoylation in regulating cytosolic translation. The comprehensive dataset of palmitoylation generated in this study provide a valuable resource for future mechanistic investigations into protein function, enhancing our understanding of plant proteomes.