mRNA m(6)A methyltransferase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: an adenosine in mRNA + S-adenosyl-L-methionine = an N(6)-methyladenosine in mRNA + H+ + S-adenosyl-L-homocysteine. This activity is the methylation of adenines in mRNA with the consensus sequence RRACH, where R is a purine, and H is C, A, or U. [EC:2.1.1.348, GOC:hjd]

mRNA m(6)A methyltransferase activity is a crucial biological process that involves the methylation of adenine (A) bases within mRNA molecules. This methylation, specifically at the N6 position of adenine, is catalyzed by a group of enzymes known as mRNA m(6)A methyltransferases. These enzymes typically form multi-protein complexes containing subunits responsible for substrate recognition, catalytic activity, and regulatory functions.

The molecular function of this activity can be broken down into several key aspects:

1. **Substrate Recognition and Binding:** The m(6)A methyltransferase complex recognizes specific mRNA sequences, often enriched with consensus motifs like "DRACH" (where D = G/A/U, R = A/G, and H = A/C/U), to ensure precise methylation. This substrate recognition involves interactions between the enzyme and the mRNA sequence, often facilitated by specific domains within the methyltransferase complex.

2. **Catalytic Activity:** The catalytic subunit of the m(6)A methyltransferase complex utilizes S-adenosyl methionine (SAM) as a methyl donor. Through a series of chemical reactions, the enzyme transfers the methyl group from SAM to the N6 position of adenine within the target mRNA sequence. This process is highly specific and ensures the addition of a methyl group only at the desired location.

3. **Regulation of mRNA Metabolism:** The m(6)A modification has been shown to play a significant role in regulating various aspects of mRNA metabolism, including:
* **Splicing:** m(6)A methylation can influence alternative splicing events, affecting the final protein product produced from a single gene.
* **Translation:** The presence of m(6)A can modulate the efficiency of translation, impacting protein synthesis.
* **Stability:** m(6)A methylation can influence mRNA stability, affecting its lifespan within the cell.
* **Transport:** m(6)A modifications can influence the transport of mRNA from the nucleus to the cytoplasm, where translation occurs.

4. **Cellular Processes and Functions:** The regulation of mRNA metabolism by m(6)A methylation is implicated in a wide range of cellular processes and functions, including:
* **Development:** m(6)A methylation plays a role in embryonic development and cell differentiation.
* **Immune responses:** This modification is involved in regulating immune responses and inflammation.
* **Stress response:** m(6)A methylation contributes to the cellular response to stress conditions.
* **Cancer:** Dysregulation of m(6)A methylation is associated with various cancers and other diseases.

In summary, mRNA m(6)A methyltransferase activity is a complex and essential biological process that influences diverse aspects of mRNA metabolism, ultimately affecting gene expression, cellular function, and organismal development. The precise mechanisms by which m(6)A methylation regulates these processes are under active investigation, but it is clear that this modification plays a pivotal role in maintaining cellular homeostasis and influencing a wide array of biological pathways.'
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Proteins (1)

Compounds (1)