MCB 2050 - The Nucleus Questions With Complete Solutions

MCB 2050 - The Nucleus Questions With Complete
Solutions


What are Nuclear Pores?
• Inner & outer membranes of nuclear envelope fuse --> pores

• Gateways between cytoplasm & nucleoplasm
Describe the Nuclear Pore complex:
Protein structure fills nuclear pore; Nuclear Pore Complex
(NPC)
– Complex supramolecular complex
• 100s of polypeptides
– Fits into the pore; reduces functional diameter
– Extends into cytoplasm & nucleoplasm
What Does the Nuclear Pore Complex (NPC) structure consist
of?
• Highly conserved
• Octagonal symmetry of overall structure organized around a
large central channel
• Inner surface of the channel lined by ‘filament-like’ proteins
– FG nucleoporins (Nups) (‘FG domains’)
• FG domains possess a unique highly disordered 2o structure
• Structural and Membrane NUPS

, filaments or the nuclear basket
• Cytoplasmic filaments
• Nuclear basket
What are FG domains?
- flexible organization that goes into the central channel

- form a hydrophobic 'mesh' (sieve-like gel) ; limits the diffusion
of macromolecules larger than 40 kDa (~39 nm in diameter
What are NUPS
- located on the cytoplasmic and nuclear side of the NPC

- linked to the central scaffold and also the cytoplasmic
filaments of the nuclear basket
What are cytoplasmic filaments
- long protein filaments that extend into the cytosol on the
cytosolic side

- involved in nuclear receptor-cargo protein recognition and
import
What is the Nuclear Basket
- 'basket-like' structure located on nuclear side of the NPC
(nuclear envelope)
- involved in nuclear receptor-cargo protein import and export
What are the functions of the Nuclear Pore Complex (NPC)?