Related Experiment Videos
Biological methylation of myelin basic protein: enzymology and biological significance
1Department of Biochemistry, School of Medicine, Korea University, Seoul, Korea.
Abstract:
Myelin is a membrane characteristic of the nervous tissue and functions as an insulator to increase the velocity of the stimuli being transmitted between a nerve cell body and its target. Myelin isolated from human and bovine nervous tissue is composed of approximately 80% lipid and 20% protein, and 30% of the protein fraction constitutes myelin basic protein (MBP). MBP has an unusual amino acid at Res-107 as a mixture of NG-monomethylarginine and NG, N'G-dimethylarginine. The formation of these methylarginine derivatives is catalysed by one of the subtypes of protein methylase I, which specifically methylates Res-107 of this protein. Evidence is presented to demonstrate an involvement of this biological methylation in the integrity and maintenance of myelin.
Insights
Biological methylation is crucial for maintaining myelin, a key component of nervous tissue insulation. This process specifically modifies myelin basic protein (MBP), ensuring nerve signal velocity.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- Myelin is a lipid-rich membrane essential for insulating nerve fibers and facilitating rapid signal transmission in the nervous system.
- Myelin basic protein (MBP) constitutes a significant portion of myelin's protein content and contains unusual methylated amino acids.
- The precise role of MBP methylation in myelin structure and function requires further elucidation.
Purpose of the Study:
- To investigate the role of biological methylation in the integrity and maintenance of myelin.
- To identify the specific enzyme responsible for methylating MBP at Res-107.
- To understand the significance of methylated arginine residues in MBP.
Main Methods:
- Isolation and analysis of myelin from human and bovine nervous tissue.
- Characterization of the protein composition of myelin, focusing on MBP.
- Identification and analysis of post-translational modifications of MBP, specifically methylation at Res-107.
- Enzymatic assays to identify the protein methylase subtype involved.
Main Results:
- Myelin is composed of approximately 80% lipid and 20% protein, with MBP being a major protein component.
- MBP contains a unique mixture of NG-monomethylarginine and NG, N'G-dimethylarginine at Res-107.
- A specific subtype of protein methylase I was identified as the catalyst for MBP methylation at Res-107.
- Evidence suggests this biological methylation is integral to myelin integrity and maintenance.
Conclusions:
- Biological methylation of myelin basic protein (MBP) at Res-107 by protein methylase I is a critical process.
- This specific methylation event plays a vital role in the structural integrity and ongoing maintenance of myelin.
- Understanding this methylation pathway offers insights into nervous system health and potential therapeutic targets.