Lecture 12

Question 1

cotranslational translocation

Answer 1

protein is being located into the ER while its being translated

Question 2

SRP

Answer 2

signal recognition particle

Question 3

BiP

Answer 3

chaperone that prevents polypeptide chain from slipping back out or premature folding

Question 4

How does cell know where a certain protein goes?

Answer 4

information is encoded in the amino acid sequence

Question 5

lipid-anchor proteins

Answer 5

not associated with plasma membrane, linked to a lipid that is associated with membrane

Question 6

Type I single pass membrane protein

Answer 6

N-term in ER, has a stop anchor sequence and gets transferred into membrane, most of protein is in ER, signal sequence cleaved

Question 7

Type II single pass membrane protein

Answer 7

C-term in ER, has Signal Anchor sequence, no cleavage

Question 8

Type III single pass membrane protein

Answer 8

N-term in ER, has SA sequence, no cleavage

Question 9

Tail anchored

Answer 9

C-term hydrophobic tail only in membrane, rest of protein in cytosol

Question 10

Lipid anchor proteins

Answer 10

precursor protein gets transferred via GPI transmidase to GPI anchor

Question 11

Protein modifications

Answer 11

mannose (carbohydrate), S-S rearrangement via PDI

Question 12

Unfolded protein response

Answer 12

BiP holds unfolded protein = causes splicing and translation of transcription factors that activate chaperones to fold protein BiP is holding

Question 13

Dislocation purpose

Answer 13

for proteins that have been unassembled or misfolded need to be removed

Question 14

Disclocation process

Answer 14

clip off modifications and mark protein for degradation