Human histone H1.5: role of phosphorylation and glycosylation in cell cycle

Linker histone H1.5 belongs to a family of proteins that organize eukaryotic DNA into a compact structure. The post-translational modifications induce conformational changes and allow the nuclear proteins to interact with chromatin which results in the regulation of transcription and gene expression during cell cycle. The O-beta-GlcNAc modification on Ser and Thr residues is as dynamic as phosphorylation. Interplay between these two modifications at the same or neighboring residues can result in diverse functional regulation of proteins. Phosphorylation of histone H1.5 is known to activate transcription and gene regulation by uncoiling of chromatin. This, in silico, study proposes that phosphorylation sites at Ser/Thr residues of linker histone H1.5 also exhibit O-GlcNAc modification potential which regulates the higher order chromatin structure by blocking phosphorylation and promoting condensation of chromatin structure. (author)