How does the nuclear pore complex work to transport material in and out of the nucleus?
The pore serves as a water filled channel and has an effective diameter of 10 nm. Therefore, transport in and out of the nucleus can occur in several ways. Diffusion This can be tested by adding different sized molecules to the cytosol and watching the rate of transport of each group. For example, molecules of: 5,000 MW are freely diffusable 17,000 MW– take 2 min to establish equilibrium 44,000 MW–take 30 min to establish equilibrium 60,000 MW–cannot move in by diffusion This concept is important because it means that mature ribosomes (with both subunits joined) cannot reenter the nucleus. Therefore, protein synthesis (translation of mRNA) must occur outside the nucleus.
