Striated muscle in vertebrates comprises large proteins which must be organized properly to contract efficiently. Z-lines in striated muscle are a sign of this organization, representing the ends of actin thin filaments, titin, nebulin or nebulette and accessory proteins required for structure and function. This gene encodes a protein which interacts with nebulin in skeletal muscle or nebulette in cardiac muscle and alpha-actinin. In addition, this gene product can interact with a protein with the I-band indicating it has a regulatory as well as structural function. Alternative splicing results in multiple transcript variants.