How are proteins retained in the ER? Two models
- Exclusion from transport vesicles to Golgi
2. retrieval from the cis golgi
How was ER retention signal discovered?
by sequence grazing: c terminal Kdel in mammals, for soluble ER proteins
Where is the KDEL receptor?
In the cis golgi
What is the job of the Er?
- to get proteins to the membrane
- glycosylation
- phosphate bond formation
- disulfide bonds
What is the issue with misfolded proteins?
creates kinks in pathways
faulty proteins may accumulate
What protein is usually delayed during production, that cuases cystic fibrosis?
phenylalanine deletion
What does UPR stand for?
Unfolded protein response
What are certain ways that cells may reduce loads of misfolded/unfolded proteins
- decrease production
- higher control of production
- fact checkers
What are a couple of key signalers of the UPR?
IRE1 and PERK
What is the IRE1 and what does it do?
it’s a kindase/endonuclease that splices its target XBP1
What does PERK do?
phosphorylates a translation initiation factor
If it gets too stressful for the cell, what does it do?
apoptosis
