protein methylation

Definition

Target type: biologicalprocess

The addition of a methyl group to a protein amino acid. A methyl group is derived from methane by the removal of a hydrogen atom. [GOC:ai]

Protein methylation is a crucial post-translational modification where a methyl group (CH3) is added to a specific amino acid residue within a protein. This process is catalyzed by enzymes called methyltransferases, which utilize S-adenosyl methionine (SAM) as a methyl donor. The addition of a methyl group can alter the protein's structure, function, and interactions with other molecules.

The process of protein methylation can be broadly divided into three steps:

1. **Recognition and Binding:** The methyltransferase recognizes and binds to the specific target protein and its corresponding amino acid residue. This recognition is often mediated by specific interactions between the enzyme and the protein's amino acid sequence and structure.

2. **Methyl Group Transfer:** The methyltransferase transfers a methyl group from SAM to the target amino acid residue. This transfer involves a complex series of chemical reactions that involve the formation of a covalent bond between the methyl group and the amino acid.

3. **Product Release and Regeneration:** After the methylation reaction is complete, the methyltransferase releases the modified protein and SAM, which is now in its demethylated form (S-adenosyl homocysteine). SAM can be regenerated by a series of enzymatic reactions, allowing for continued methylation.

Protein methylation can occur on various amino acid residues, including lysine, arginine, histidine, and glutamate. The specific amino acid residue targeted for methylation can influence the protein's function.

**Lysine methylation:** Often found in histone proteins, lysine methylation plays a crucial role in gene regulation. It can activate or repress gene expression depending on the specific lysine residue and the number of methyl groups added.

**Arginine methylation:** Predominantly found in signaling proteins, arginine methylation can alter protein-protein interactions and signaling pathways.

**Histidine methylation:** Less common compared to lysine and arginine methylation, histidine methylation is involved in diverse cellular processes, including signal transduction and DNA repair.

**Glutamate methylation:** A relatively new discovery, glutamate methylation has been implicated in neuronal function and synaptic plasticity.

Protein methylation is a highly dynamic process, with specific methyltransferases and demethylases (enzymes that remove methyl groups) controlling the methylation state of proteins. This reversible nature allows for precise regulation of protein function and cellular processes.

Protein methylation is essential for a wide range of biological functions, including:

* **Gene regulation:** Controlling gene expression through modifications of histone proteins
* **Signal transduction:** Modulating signaling pathways by altering protein-protein interactions
* **Cellular development:** Regulating cell growth, differentiation, and apoptosis
* **Immune response:** Influencing immune cell function and activation
* **Disease pathogenesis:** Dysregulation of protein methylation is implicated in various diseases, such as cancer, neurological disorders, and autoimmune diseases.

Understanding the intricate mechanisms of protein methylation is crucial for elucidating the complexity of cellular processes and developing novel therapeutic strategies for various diseases.'
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Proteins (3)

Compounds (21)