L 25

Question 1

How are proteins retained in the ER? Two models

Answer 1

1. Exclusion from transport vesicles to Golgi

2. retrieval from the cis golgi

Question 2

How was ER retention signal discovered?

Answer 2

by sequence grazing: c terminal Kdel in mammals, for soluble ER proteins

Question 3

Where is the KDEL receptor?

Answer 3

In the cis golgi

Question 4

What is the job of the Er?

Answer 4

1. to get proteins to the membrane
2. glycosylation
3. phosphate bond formation
4. disulfide bonds

Question 5

What is the issue with misfolded proteins?

Answer 5

creates kinks in pathways

faulty proteins may accumulate

Question 6

What protein is usually delayed during production, that cuases cystic fibrosis?

Answer 6

phenylalanine deletion

Question 7

What does UPR stand for?

Answer 7

Unfolded protein response

Question 8

What are certain ways that cells may reduce loads of misfolded/unfolded proteins

Answer 8

1. decrease production
2. higher control of production
3. fact checkers

Question 9

What are a couple of key signalers of the UPR?

Answer 9

IRE1 and PERK

Question 10

What is the IRE1 and what does it do?

Answer 10

it’s a kindase/endonuclease that splices its target XBP1

Question 11

What does PERK do?

Answer 11

phosphorylates a translation initiation factor

Question 12

If it gets too stressful for the cell, what does it do?

Answer 12

apoptosis