Proteome-wide analysis of Lysine 2-Hydroxyisobutyrylation in Aspergillus fumigatus

Aspergillus fumigatus is the main culprit of invasive aspergillosis, which has a high mortality rate in immunocompromised patients. Lysine 2-hydroxyisobutyrylation is a highly conserved posttranslational modification found in a wide variety of organisms. In this study, we survey the biological impact of 2-hydroxyisobutyrylation on lysine residuals (Khib) in A. fumigatus. Using an antibody-enrichment approach along with the traditional LC-MS/MS method, the pattern of Khib-modified proteins and sites were analyzed in one wild type strain of A. fumigatus. We identified 3494 Khib-modified proteins with 18091 modified sites in this strain, and a more detailed bioinformatics analysis indicated that the Khib-modified proteins are involved in a wide range of cellular functions with diverse subcellular locations. Functional enrichment analysis featured several prominent functional pathways, including ribosome, biosynthesis of amino acids and nucleocytoplasmic transport – of which the ribosome pathway is the most affected pathway. When compared with other reported Khib eukaryotes, both Khib-modified sites and Khib-modified proteins also remained the highest. It proves that this modification is of great importance in A. fumigatus. At the same time, several enzymes in the fungal ergosterol synthesis pathway are modified with Khib. These bioinformatic results suggest that 2-hydroxyisobutyrylation may play an indispensable role in the regulation of the ribosomal biogenesis and the process of fungal resistance. Findings in this study may provide new insights for studying PTM-associated mechanisms in fungal development and antifungal drug development.