Question

A new dangerous virus has emerged which produced an miRNA that represses the protein Ran. Which of the following scenarios is most likely to occur for nuclear transport relying on Ran?

Proteins with NLSs would be transferred to the nucleus but not released from Imp alpha or beta

Nuclear localizing sequences (NLSs) would not be able to bind to Imp-alpha subunit.

All protein transport across to the nucleus would come to a halt.

There would be too much Ran protein produced resulting in aggregation of the protein and dangerous effects to the NPC system.

NLSs would not be able to bind to Imp-beta subunit.

Answer 1

Ran plays important role in transport of non coding RNAs and Protein in between cytoplasm and nucleus. They interact with the Karyopherins which regulate the binding and release of cargo molecules.

These cargo proteins carries nuclear localizing signal and binds with importins which helps them to transport inside the nucleus. Inside the Nucleus RanGTP binds with importin which releases the cargo. After that cargo binds with the exportin which have the RanGTP attached and this complex molecules came out of the nucleus. Inside the cytoplasm the RanGTP get converted into RanGDP through hydrolysis which separates the cargo from exportin and RnaGDP complex.

As per given options all are linked with the Ran

So Represses of Ran means the protein transport across the nucleus will get affected.

Nuclear localizing signal protein will not able to bind with the imp-beta subunit.