Protein Lactylation and Metabolic Regulation of the Zoonotic Parasite Toxoplasma gondii

The biology of Toxoplasma gondii, the causative pathogen of one of the most wide-spread parasitic diseases remains poorly understood. Lactate, which is derived from glucose metabolic pathways, is considered to be not only an energy source in a variety of organisms including Toxoplasma gondii, but also a regulatory molecule that participates in gene activation and protein functioning. Lysine lactylation is a type of posttranslational modifications (PTMs) that was recently associated with chromatin remodeling, but lysine lactylation of histone and non-histone proteins has not yet been studied in T. gondii. To examine the prevalence and function of lactylation in T. gondii parasites, we mapped the lactylome of proliferating tachyzoite cells and found 1964 lactylation sites on 955 proteins in the T. gondii RH strain. The lactylated proteins were distributed in multiple subcellular compartments and were closely related to a wide variety of biological processes, including mRNA splicing, glycolysis, aminoacyl-tRNA biosynthesis, RNA transport, and multiple signaling pathways. We also performed chromatin immunoprecipitation sequencing (ChIP-seq) analysis with a lactylation specific antibody, the results revealed that histone H4K12la and H3K14la were enriched in the promoter and exon regions of Toxoplasma gondii genes associated with microtubule-based movement and cell invasion. We further confirmed the de-lactylase activity of histone deacetylase TgHDACs 2, 3, and 4, and that treatment with anti-histone acetyltransferase (TgMYST-A) antibodies profoundly reduced protein lactylation in the parasites. This study offers the first dataset of the global lactylation proteome and provides a basis for further dissection of the functional biology of Toxoplasma gondii.