ADP-ribosylation of human myelin basic protein

Area of Science:

• Biochemistry
• Neuroscience

Background:

• Myelin basic protein (MBP) is a key component of myelin.
• ADP-ribosylation is a post-translational modification with roles in cellular processes.

Purpose of the Study:

• To investigate the ADP-ribosylation of myelin basic protein (MBP) using cholera toxin as a model.
• To characterize the modification of different MBP charge isomers.

Main Methods:

• ADP-ribosylation of isolated myelin membranes using [32P]NAD+ and cholera toxin.
• Separation of MBP charge isomers using alkaline-urea gel electrophoresis and CM52 chromatography.
• Analysis of ADP-ribose incorporation into different MBP components.

Main Results:

• Myelin basic protein (MBP) is the major radioactive product of ADP-ribosylation in myelin membranes.
• Cholera toxin facilitates ADP-ribosylation of MBP, serving as a suitable model.
• MBP exhibits charge heterogeneity, with distinct isomers showing differential incorporation of ADP-ribose.
• The ADP-ribosyl bond in MBP has a half-life of approximately 80 minutes, suggesting an N-glycosidic linkage to arginine residues.

Conclusions:

• Cholera toxin-mediated ADP-ribosylation provides insights into myelin protein modification.
• MBP charge isomers exhibit varying susceptibility to ADP-ribosylation.
• The findings suggest a specific N-glycosidic linkage involving arginine residues in MBP modification.