H3S28P

H3S28P

Amino acid phosphorylations

H3S28P refers to the phosphorylation of the serine residue at position 28 on the histone H3 protein. This post-translational modification plays a crucial role in the regulation of chromatin structure and function, impacting processes such as gene expression, DNA repair, and cell cycle progression.

Structure and Function

Histone H3 is one of the core histone proteins that form the nucleosome, the fundamental unit of chromatin. The phosphorylation of serine 28 (S28) on histone H3 is a dynamic modification that can influence chromatin compaction and accessibility. This modification is often associated with active transcription and is thought to facilitate the recruitment of specific chromatin remodeling complexes.

Biological Significance

H3S28 phosphorylation is involved in several key cellular processes:

• Gene Expression: Phosphorylation at H3S28 is linked to the activation of immediate-early genes in response to various stimuli. It is often found in conjunction with other histone modifications, such as acetylation, to promote an open chromatin state conducive to transcription.

• Cell Cycle Regulation: During mitosis, H3S28P is associated with chromosome condensation. The modification is catalyzed by Aurora B kinase, a key regulator of mitotic events.

• Stress Response: H3S28 phosphorylation is also implicated in the cellular response to stress, including DNA damage. It may help in recruiting repair machinery to sites of damage.

Enzymes Involved

The phosphorylation of H3S28 is primarily mediated by Aurora kinases, particularly Aurora B. These kinases are active during mitosis and are essential for proper chromosome alignment and segregation.

Interactions with Other Modifications

H3S28 phosphorylation often occurs in conjunction with other histone modifications, such as H3K27 acetylation (H3K27ac). This combination is thought to create a "histone code" that signals specific chromatin states and regulatory outcomes.

Research and Clinical Implications

Understanding the role of H3S28 phosphorylation in chromatin dynamics and gene regulation has significant implications for cancer research. Aberrant phosphorylation patterns are often observed in cancer cells, and targeting the enzymes responsible for these modifications is a potential therapeutic strategy.

Related Pages

• Histone modification
• Chromatin
• Aurora kinase
• Gene expression