Members of this family belong to the nucleor pore complex, NPC, the only gateway between the nucleus and the cytoplasm. The NPC consists of several subcomplexes each one of which is made up of multiple copies of several individual Nup, Nic or Sec protein subunits. In yeast, this Nup or nucleoporin subunit is numbered Nup53, Nup40 in Schizo. pombe and in vertebrates as Nup35. This subunit forms part of the inner ring within the membrane and interacts directly with Nup-Ndc1, considered to be an anchor for the NPC in the pore membrane. This region of the Nup is the RNA-recognition region.