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Figure 3. Biglycan regulates the sarcolemmal expression and membrane trafficking of the NODS complex proteins. In normal muscle, biglycan is expressed in a core polypeptide form as well as a proteoglycan form that binds to 
-dystroglycan via its GAG side chains. In biglycan null animals the levels of dystrobrevins-1 and -2, 1- and ß1-syntrophin and nNOS at the sarcolemma are reduced. Moreover, there is an increase in the level of syntrophins associated with intracellular membranes. Intramuscular injection of recombinant biglycan core polypeptide restores the sarcolemmal association of the dystrobrevins and ß1/2 syntrophins.
