Large-scale identification of lysine crotonylation reveals its potential role in oral squamous cell carcinoma

Abstract

Abstract Background Lysine crotonylation, a newly identified type of posttranslational modification, has been implicated in the regulation of various biological processes. However, its role in oral squamous cell carcinoma (OSCC) remains unknown. The study aimed to reveal the global crotonylome in OSCC under hypoxic conditions and explore the potential underlying regulatory mechanism of crotonylation in OSCC. Methods Liquid-chromatography fractionation, affinity enrichment of crotonylated peptides and high-resolution mass spectrometry were used to detect differential crotonylation in CAL27 cells cultured under hypoxia. The obtained data were further analyzed through bioinformatics analysis to reveal the involved biological processes and pathways of the dysregulated crotonylated proteins. A site-mutated plasmid was used to investigate the effect of crotonylation on Heat Shock Protein 90 Alpha Family Class B Member 1 (HAP90AB1) function. Results The large-scale of crotonylome analysis revealed 1563 crotonylated modification sites on 605 proteins in CAL27 cells under hypoxia. Bioinformatics analysis showed that histone contonylation levels decreased while up-regulated crotonylated proteins were mainly concentrated in non-histone proteins. Notably, glycolysis-related proteins were prominently up-regulated among the identified crotonylated proteins, with HSP90AB1 having the most significant changes. Further experimental results confirmed that mutating lysine 265 of HSP90AB1 into a silent arginine weakened its function in promoting glycolysis. Conclusion Our study mapped the crotonylation modification of proteins under hypoxia in OSCC and uncovered the biological processes and pathways of the dysregulated crotonylated proteins. Crotonylation of HSP90AB1 in hypoxic conditions may promote the glycolysis regulation ability in OSCC, providing novel insights into the regulatory mechanism of crotonylation in OSCC under hypoxia and potential therapeutic targets for OSCC treatment.