Required for normal myelination and for normal organization of the cytoplasm and the formation of Cajal bands in myelinating Schwann cells (PubMed:22764250). Required for normal PRX location at appositions between the abaxonal surface of the myelin sheath and the Schwann cell plasma membrane (PubMed:22764250). Possibly involved in membrane-cytoskeleton interactions of the central nervous system. Interacts with PRX; this enhances phosphorylation (PubMed:22764250). Identified in a dystroglycan complex that contains at least PRX, DRP2, UTRN, DMD and DAG1 (PubMed:11430802). Detected in Schwann cells at periaxonal myelin membranes. Detected in quadriceps nerve Schwann cells (PubMed:22764250). Detected in sciatic nerve (PubMed:11430802, PubMed:22764250). Detected in trigeminal nerve Schwann cells (at protein level) (PubMed:11430802). Detected in brain and spinal cord (PubMed:8640231). Mice with a Schwann cell-specific gene disruption show no obvious impairment of nerve conduction velocity and display no visible defects of their motor skills. After six months, about 6% of their nerve fibers present myelination defects, including myelin outfoldings, focal hypermyelination, and onion bulbs with thin myelin and supernumerary Schwann cells. At the molecular level, Schwann cell-specific gene disruption impairs formation of Cajal bands and location of Prx in patches that colocalize with appositions between the abaxonal surface of the myelin sheath and the Schwann cell plasma membrane. Cytoplasm from mutant Schwann cells forms an annulus under the cell membrane, insted of being strictly compartmentalized. Besides, mutant nerves display increased numbers of Schmidt-Lanterman incisures.