LAUSR

Histone modification is critical for the process of autophagy in osteosarcoma. Whether phosphorylated histone H4 (H4) mediates autophagy remains to be seen. Here, we aimed to investigate the effects of general control nonderepressible 5 (GCN5)-evoked phosphorylation of H4 on autophagy. Osteosarcoma bone cell lines Saos-2, MG-63, and HOS cells were applied. Kinase activity was monitored in in vitro kinase assay buffer. Immunoprecipitation and glutathione S-transferase (GST) pull-down assay were exploited to confirm the association of GCN5 to H4. Furthermore, we determined green fluorescent protein (GFP)-tagged light chain 3 (LC3), long-lived protein, gene expression, and transcriptional activity. We found that a direct connection of GCN5 to H4 existed in osteosarcoma bone cells. Results indicated that GCN5 was implicated in the modulation of H4 phosphorylation at serine 1 (Ser1). GCN5-mediated phosphorylation of H4 at Ser1 facilitated the formation of GFP-LC3, conversion of LC3-I into LC3-II and transcriptional activity of autophagy-related genes. We reported that GCN5 was included in the modulation of H4 phosphorylation at Ser1. Fortification of epigenetic phosphorylated marks at Ser1 of H4 by GCN5 sensitized osteosarcoma bone cells to autophagy.