Nucleoporins are proteins that make up the nuclear pore complex, a large structure embedded in the nuclear envelope of eukaryotic cells. They play a crucial role in regulating the transport of molecules between the nucleus and the cytoplasm, allowing essential substances like RNA and proteins to move in and out of the nucleus. These proteins are diverse in structure and function, with some forming the central channel of the pore while others provide structural support. Nucleoporins are vital for maintaining cellular function and are involved in various processes, including gene expression and cell signaling, highlighting their importance in cellular biology.