Adapter protein that binds to and probably organizes the subcellular localization of a variety of proteins. May link various receptors to the actin cytoskeleton and the dystrophin glycoprotein complex (By similarity). May participate in regulating the subcellular location of diacylglycerol kinase-zeta to ensure that diacylglycerol is rapidly inactivated following receptor activation. Isoform 1, but not isoform 2, interacts with the dystrophin protein DMD and related proteins DTNA and DTNB. Interacts with DGKZ. Mainly cytoplasmic and weakly nuclear. Brain specific. In CNS, it is expressed in the perikaryon and proximal portion of the neuronal processes. Strong expression in the hippocampus, neuron-rich dendate granule cells, and pyramidal cell layers. Highly expressed in neurons of the cerebral cortex. Also expressed in the cerebellar cortex, deep cerebellar nuclei, thalamus, and basal ganglia. No expression in muscle cells. The PDZ domain binds to the last three or four amino acids of DGKZ. The association with dystrophin or related proteins probably leaves the PDZ domain available to recruit proteins to the membrane. Belongs to the syntrophin family.