Acylation of myelin Po protein is required for adhesion

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• Myelin Po protein is essential for compacting myelin sheaths in the nervous system.
• The extracellular domains of Po mediate homophilic interactions, maintaining myelin structure.
• The cytoplasmic domain and post-translational modifications, like acylation, can influence Po protein function.

Purpose of the Study:

• To investigate the role of Cys 153 acylation in the adhesive properties and stability of myelin Po protein.
• To determine if mutations at Cys 153 affect Po protein's interaction with the cytoskeleton or its membrane clustering.

Main Methods:

• Site-directed mutagenesis was used to create a Cys 153 to alanine (C153A) mutant of the Po protein.
• Acylation status, adhesion, membrane clustering, and cellular turnover rates of wild-type and C153A Po were analyzed in transfected Chinese hamster ovary cells.

Main Results:

• The C153A Po mutant was not acylated and exhibited a significant loss of adhesive properties.
• C153A Po, similar to wild-type Po, showed membrane clustering and interaction with the cytoskeleton.
• The cellular turnover rate of C153A Po was approximately four times faster than that of wild-type Po, indicating increased instability.

Conclusions:

• Acylation of myelin Po protein at Cys 153 is critical for its adhesive function.
• The increased instability and rapid turnover of the non-acylated C153A Po mutant likely contribute to its inability to maintain myelin adhesion.