Dystrophin and the α-dystrobrevins bind directly to the adapter protein syntrophin to form membrane-associated scaffolds. At the blood–brain barrier, α-syntrophin colocalizes with dystrophin and the α-dystrobrevins in perivascular glial endfeet and is required for localization of the water channel aquaporin-4. Earlier we have shown that localization of the scaffolding proteins γ2-syntrophin, α-dystrobrevin-2, and dystrophin to glial endfeet is also dependent on the presence of α-syntrophin. In this study, we show that the expression levels of α-syntrophin, γ2-syntrophin, and dystrophin at the blood–brain barrier are reduced in α-dystrobrevin-null mice. This is the first demonstration in which assembly of an astroglial protein scaffold containing syntrophin and dystrophin in perivascular astrocytes is dependent on the presence of α-dystrobrevin.