Which statement best describes the energy requirements for transport through the nuclear pore complex, particularly for large cargo?

Which statement best describes the energy requirements for transport through the nuclear pore complex, particularly for large cargo?

• A. Larger cargo requires energy via Ran GTPase for transport.
• B. Energy is not required for any transport.
• C. Energy is required only for export.
• D. Energy is required only for diffusion.

Answer: (A)

Passing large cargo through the nuclear pore complex requires energy from the Ran GTPase system to move cargo through the selective barrier and to ensure directionality. Small molecules can diffuse freely without input, but big cargo rely on transport receptors (importins and exportins) that shuttle cargo through the FG-nucleoporin meshwork. The Ran cycle—high Ran-GTP in the nucleus promoting cargo release, and higher Ran-GDP in the cytoplasm resetting receptors—provides the energy and direction for this process. In short, large cargo need energy from Ran GTPase to be transported, whereas diffusion of small molecules is energy-independent.

Passing large cargo through the nuclear pore complex requires energy from the Ran GTPase system to move cargo through the selective barrier and to ensure directionality. Small molecules can diffuse freely without input, but big cargo rely on transport receptors (importins and exportins) that shuttle cargo through the FG-nucleoporin meshwork. The Ran cycle—high Ran-GTP in the nucleus promoting cargo release, and higher Ran-GDP in the cytoplasm resetting receptors—provides the energy and direction for this process. In short, large cargo need energy from Ran GTPase to be transported, whereas diffusion of small molecules is energy-independent.