Protein Sorting at the Cytoplasm Quiz

What is the function of nuclear pore complexes (NPCs) in the nuclear envelope?

What type of proteins are directed into the nucleus?

What is the role of import receptors (importins) in protein translocation?

What characterizes proteins with a nuclear export sequence (NES)?

Which complex locally dissolves the gel-like mesh and can diffuse into and within the NPC pore?

What promotes cargo dissociation for importins in the nucleus?

What triggers GTP hydrolysis for Ran-GDP?

What do exportins promote in the nucleus?

Which subunit of importin binds the nuclear localization signal (NLS)?

What prevents mitochondrial proteins from folding in the cytoplasm?

Which systems move polypeptide chains through the two membranes of the mitochondria?

What do exportins bind to guide their cargo to the cytosol?

Nuclear Pore Complexes (NPCs)

Function to transport molecules between the nucleus and cytoplasm.

Protein Transport

Proteins with a nuclear localization signal (NLS) are directed into the nucleus.
Import receptors (importins) bind to these proteins and mediate their transport into the nucleus.

Importin Function

Import receptors (importins) bind to proteins with a nuclear localization signal (NLS) and facilitate their transport into the nucleus.

Nuclear Export Sequence (NES)

Characterized by proteins that are exported from the nucleus to the cytoplasm.
Proteins with a NES are recognized by exportins, which facilitate their export from the nucleus.

Translocation through NPC

The FG-Nup complex locally dissolves the gel-like mesh and can diffuse into and within the NPC pore.

Importin-Cargo Dissociation

Ran-GTP promotes cargo dissociation for importins in the nucleus.

Ran-GTP Hydrolysis

Triggered by the binding of Ran-GTP to importin, causing a conformational change that triggers GTP hydrolysis.

Exportin Function

Exportins bind to proteins with a NES and promote their export from the nucleus to the cytosol.

Importin Subunit

The α subunit of importin binds the nuclear localization signal (NLS) of proteins.

Mitochondrial Protein Folding

Chaperone proteins prevent mitochondrial proteins from folding in the cytoplasm, ensuring proper targeting to the mitochondria.

Mitochondrial Protein Transport

The TIM23 and TOM complexes move polypeptide chains through the two membranes of the mitochondria.

Exportin-Cargo Binding

Exportins bind to proteins with a NES, guiding their cargo to the cytosol.

Test your knowledge of protein sorting at the cytoplasm with this quiz. Explore the linear signal sequences for protein translocation into organelles, specifically focusing on the nuclear envelope and nuclear pore complexes. Perfect for students of BIOL2020 looking to reinforce their understanding of protein sorting mechanisms.