Summary
A large protein assembly that gates the nuclear envelope, controlling traffic of RNA and proteins via importins.
In depth
Each pore is built from around 30 different nucleoporins and has an eightfold symmetry. Small molecules pass freely, while large cargo needs a nuclear localisation signal recognised by importins; the Ran GTPase gradient gives direction.
A mesh of disordered FG-repeat proteins in the channel works as a selective barrier. Thousands of pores sit in each nuclear envelope.
Each pore passes millions of molecules each minute, and transport rates reach hundreds of molecules per pore per second. Import works in steps: importin binds the nuclear localisation signal, moves through the FG-repeat network, and in the nucleus Ran-GTP causes release of the cargo; the importin returns and Ran-GTP is hydrolysed in the cytoplasm, so the cycle uses GTP to set direction.
mRNA export needs specific export factors and is linked to splicing, which ensures only mature RNAs leave. Viruses such as HIV and herpes use the pore to deliver their genome.
Remember: the pores are not simple holes, they are selective gates, and the nucleus does not make a protein it cannot import.
Frequently asked questions
What is Nuclear Pore Complex?
A large protein assembly that gates the nuclear envelope, controlling traffic of RNA and proteins via importins.
Which area of biology covers Nuclear Pore Complex, and how advanced is it?
Nuclear Pore Complex is one of the 52 topics in Cell Biology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Facilitated Diffusion, Cytoplasm, Cell Signalling.
Can you give an example of Nuclear Pore Complex?
Steroid hormone receptors enter the nucleus only after hormone binding exposes their localisation signal.
What should I learn before Nuclear Pore Complex?
Work through the Beginner topics in Cell Biology first, such as Cell Theory, Prokaryotic Cell, Eukaryotic Cell, then return to Nuclear Pore Complex. Advanced topics assume the Intermediate vocabulary.
What topics are related to Nuclear Pore Complex?
The closest topics to Nuclear Pore Complex are Facilitated Diffusion, Cytoplasm, Cell Signalling, Plasma Membrane. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Nuclear Pore Complex?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Nuclear Pore Complex. To practise the whole of Cell Biology, use the Cell Biology quiz.
How is Nuclear Pore Complex different from Facilitated Diffusion?
Nuclear Pore Complex: A large protein assembly that gates the nuclear envelope, controlling traffic of RNA and proteins via importins. Facilitated Diffusion: Passive transport of ions and polar molecules down a gradient through channel or carrier proteins. Read both side by side and note what each one explains.
How should I study Nuclear Pore Complex step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Facilitated Diffusion and explain the difference aloud. Finally, take the Cell Biology quiz and come back to this page for any question you miss.