Protein acetylation as a novel post-translational modification of plant peroxisomal proteins

Plant peroxisomes compartmentalize many important metabolic functions, but little is known about how these pathways are regulated at the post-translational level. A few plant peroxisomal proteins have been shown to be subjected to reversible phosphorylation or ubiquitination, but other post-translational modifications are hardly known for peroxisomes from animals, fungi, and plants. We here address the question of whether plant peroxisomal metabolism might be regulated by protein acetylation. We summarize available knowledge on protein acetylation in plastids and mitochondria, focusing on the catalytic machinery and the regulation of target enzymes. We screened global acetylome studies of Arabidopsis for known proteins of peroxisomes that are N-terminally or Lys-acetylated. For selected matrix proteins, we mapped the acetylated Lys sites onto their AlphaFold 3D models to predict their effect on enzyme activity and oligomerization. We also summarize knowledge on two Arabidopsis acetyl transferases that have recently been identified as novel peroxisomal matrix proteins. We deduce their evolution in peroxisomes and partially their functions, as far as they can be predicted from available structural models. This information allows us to identify experimental strategies to define the postulated new regulatory mechanism of protein acetylation for plant peroxisomes in the near future.