Neural Cell Adhesion Molecule - Minor Exons

Minor Exons

Another layer of complexity is created by the insertion of other "minor" exons in the NCAM transcript. The two most notable are:

• the VASE (VAriable domain Spliced Exon) exon which is thought to correlate with an inhibition of the neurite outgrowth promoting properties of NCAM.
• the MSD (Muscle Specific Domain), which is thought to play a positive role in myoblast fusion. In skeletal muscle it is found in all three NCAM isoforms, increasing their MW, giving NCAM-125, NCAM-145, and NCAM-185 isoforms, but is most commonly found in the NCAM-125 isoform.