Matrilins 1-4 are extracellular-matrix proteins that are involved in the formation of collagen-dependent and collagen-independent filamentous networks, but their specific functions are mostly unknown. In this study, Dieter Riethmacher and colleagues () study matrilin-2-deficient mice (which were previously found to have a normal phenotype) to investigate whether matrilin 2 is important in nervous tissue, in which it is reportedly expressed. They show that matrilin 2 is expressed in mouse Schwann cells (SCs) during development and following peripheral-nerve injury in adult mice. Two types of migration assays reveal that matrilin-2-deficient SCs have defective migration and adhesion abilities in vitro. In addition, they report the remarkable finding that matrilin 2 supports axonal growth in vitro as efficiently as laminin, the most potent known enhancer of axonal growth. In vivo experiments show that, although matrilin 2 is expressed at low levels in adult mice, its expression is induced following peripheral-nerve injury. Furthermore, nerve regeneration following injury was slowed in matrilin-2-deficient mice. These findings characterise a novel SC-derived factor that is important for optimal peripheral-nerve regeneration.
