Protein Entry into the Nucleus

Question 1

Nucleus Structure

Answer 1

-double bilayer, thicker than the plasma membrane
-outer membrane is continuous with endoplasmic reticulum
-highly regulated by nuclear pore complex

Question 2

Nuclear pore details

Answer 2

-gateway for molecules to enter the nucleus
-small H2O molecules can pass freely
-nucleoporin proteins fill center of the channel
-regulates protein entry

Question 3

Importance of nuclear localization signal (NLS)

Answer 3

-composed of exposed lysines and/or arginines
-formed by multiple signal sequences that form a patch
-transports fully-folded proteins so signal patches are exposed

Question 4

Components of active transport to the nucleus?

Answer 4

-cytosolic proteins (nuclear transport proteins) bind to NLS for import through nuclear pore
-requires RAN (a GTPase) for getting delivered to nucleus and then cargo is released and nuclear transport proteins go back to Cytosol