4: Nucleus and ER

Question 1

Transport pathways using importin-beta type nuclear transport receptors

Answer 1

1. importing-beta like nuclear transport receptors

2. Ran

Question 2

Transport pathways using receptors with NTF2-domains

Answer 2

1. majority of mRNA export
2. Ran import
3. Cap G import

Question 3

Transport pathways using Hikeshi

Answer 3

1. HSC70 only known substrate
2. heat-shock induced
3. transport ATP-driven, binds HSC70-ATP and releases HSC70-ADP

Question 4

Transport across biological membranes - main types

Answer 4

1. Transport of newly synthesized proteins into the external environment (secretion)
2. Transport of newly synthesized proteins into intracellular compartments
3. Transport of proteins to a compartment for degradation

Question 5

Main phases of the transmembrane protein transport

Answer 5

1. Targeting of the proteins to the site of translocation in the membrane.
2. Transport of proteins across the membrane(s)
3. Modification/Folding/Quality Control in the target compartment

Question 6

Anchoring of proteins at the cytoplasmic side

Answer 6

1. Myristoylation
2. S-acylation
3. Isoprenylation

Question 7

Anchoring of proteins at the extracytoplasmic side

Answer 7

1. GPI-anchor

2. palmitate

Question 8

Modifications in the ER lumen

Answer 8

1. Signal peptide cleavage
2. N-linked glycosylation
3. GPI-anchor addition
4. Prolyl hydroxylase
5. Lysyl hydroxylase
6. Glutamyl carboxylase