Final answer:
Nuclear pore complexes (NPCs) are made of proteins, specifically nucleoporins. These nucleoporins come together to form a large complex that spans the nuclear envelope. NPCs have a crucial role in controlling the transport of molecules between the nucleus and the cytoplasm.
Step-by-step explanation:
The nuclear pore complexes (NPCs) are made of proteins. These proteins form the structure of the NPC and are responsible for its functions. The main protein components of NPCs are known as nucleoporins. These nucleoporins come together to form a large complex that spans the nuclear envelope.
Nuclear pore complexes are composed of multiple copies of different nucleoporins, which include FG repeat-containing nucleoporins and scaffold nucleoporins. The FG repeat-containing nucleoporins form a meshwork that lines the central channel of the NPC, while the scaffold nucleoporins provide structural support to the complex. Additionally, there are membrane proteins associated with the nuclear envelope that anchor the NPC to the membrane.
The nucleoporins in NPCs have various functions. They control the transport of molecules between the nucleus and the cytoplasm by acting as selective gates. The FG repeat-containing nucleoporins have hydrophobic regions called FG repeats, which interact with transport factors and regulate their movement through the NPC. The scaffold nucleoporins help to stabilize the structure of the NPC and regulate its assembly and disassembly.