Description
Histone H3 is a nuclear protein and a component of the nucleosome core, a basic unit of chromatin, that is essential for organizing genomic DNA in eukaryotic nuclei. It is a globular protein that contains an unstructured N-terminal tail that extends outside of the nucleosome core and is subject to various post-translational modifications (PTMs), including methylation, phosphorylation, acetylation, and citrullination. Histone H3 PTMs function as epigenetic regulators of gene transcription by affecting chromatin structure and providing binding sites for many transcription factors, thus regulating several cellular functions including gene expression, cell cycle, and DNA replication and repair. Differential methylation of histone H3 at various lysine residues is catalyzed by SET domain-containing methyltransferases and marks sites of transcriptional activation or repression. Citrullination of histone H3 by protein arginine deiminase 4 (PAD4; Item Nos. 10500 | 25915 | 28910) or PAD2 induces the release of neutrophil extracellular traps (NETs), a network of decondensed DNA and intracellular proteins secreted by neutrophils as a pathogen defense mechanism. Histone H3 mutations have been found in patients with diffuse intrinsic pontine glioma, leukemia, or chondroblastoma.
