The text discusses the nuclear pore complex (NPC), a large protein complex responsible for regulating transport between the cytoplasm and nucleus in eukaryotic cells. It is composed of over 30 different proteins and forms channels across the nuclear envelope. Recent evidence suggests that the NPC also plays a role in gene expression. It is one of the largest macromolecular assemblies in the cell and allows for two-way transport of nucleic acids and other components.