Question

the gene for a protein gets a mutation so that the protein's nuclear localization sequence (NLS) no longer works. where in the cell the mutated protein will end up? and why?

Answer 1

The mutated protein will end up in plasma membrane. The newly synthesized proteins at ribosomes move to the endoplasmic reticulum and from endoplasmic reticulum goes to the golgi apparatus for final targeting. The proteins from golgi apparatus distributed to different targets according to the signal sequences present on the proteins. Proteins move to either cell membrane or endosome or different cell organelles. In the absence of any signal sequence the protein moves to the cell membrane by the constitutive process.

Here nuclear localisation sequence is responsible for targeting the protein into nucleus but here the protein is mutated and thus in the absence of signal sequence the protein will move to the plasma membrane.