Lecture 11 - Protein homeostasis 1

Question 1

protein homeostasis is the maintaining of the correct amount of what where?

Answer 1

functional proteins inside and out of the cell

Question 2

which molecule is an example of protein regulation by negative feedback?

Answer 2

p53

Question 3

which molecule binds to p53 and targets it for degradation by the proteasome?

Answer 3

Mdm2

Question 4

cellular stress leads to an …… of p53, leading to an increase in …… therefore

Answer 4

increase, Mdm2

Question 5

what are the 6 stages in the life cycle of a protein?

Answer 5

synthesis, folding, transport, modifications, function, degradation

Question 6

give an example of a signalling pathway which leads to changes in translation when dysregulated in protein synthesis?

Answer 6

mTOR

Question 7

name the 3 types of protein folding

Answer 7

chaperone independent, Hsp-70 assisted, Hsp-70 and chaperonin complex assisted

Question 8

in chaperone independednt folding, where does the protein fold as it is synthesised?

Answer 8

on the ribosome

Question 9

in Hsp-70 assisted protein folding, Hsp-70 binds to what as they are synthesised to help them fold?

Answer 9

newly forming polypeptides

Question 10

Chaperones prevent misfolded or
incompletely assembled proteins
from exiting which cellular structure?

Answer 10

the ER

Question 11

the unfolded protein response (UPR) is caused by an increase of what? what does the UPR lead to?

Answer 11

misfolded proteins in the ER, apoptosis

Question 12

name the 4 reversible covalent protein modifications

Answer 12

phosphorylation, glycosylation, acetylation, ubiquitination

Question 13

undesired protein modifications come from which 2 reactive species?

Answer 13

ROS, RNS

Question 14

name the 2 major classes of protein damage

Answer 14

conformational and covalent

Question 15

name some causes of conformational changes to proteins

Answer 15

heating, free radicals, chemicals, pH change

Question 16

name some causes of covalent damage to proteins

Answer 16

oxidation, isomerisation, carbonylation, formation of isoaspartate

Question 17

give an example of a molecular chaperone

Answer 17

Hsp90

Question 18

after stress what happens to the regulation of molecular chaperones? what do they do to proteins?

Answer 18

they are upregulated, can fold proteins, prevent protein aggregation, target proteins for degradation

Question 19

which 2 heat shock chaperone proteins are involved in the stress response?

Answer 19

Hsp70 and 90

Question 20

which 2 heat shock chaperone proteins are involved in preventing aggregation?

Answer 20

Hsp40 and small heat shock proteins

Question 21

which 3 heat shock chaperone proteins are involved in protein folding?

Answer 21

Hsp60, 70, 90

Question 22

which heat shock protein chaperone is anti apoptotic?

Answer 22

Hsp60

Question 23

which 2 heat shock chaperone proteins are involved in protein degradation?

Answer 23

Hsp70, 90

Question 24

which heat shock protein chaperone interacts with steroid receptors?

Answer 24

Hsp90

Question 25

in the prevention of protein aggregation, which exposed part of the misfolded proteins do chaperons bind to, to stop proteins sticking ?

Answer 25

hydrophobic region

Question 26

which gene regulates the txn of heat shock genes?

Answer 26

HSF1

Question 27

which gene is normally present as inactive monomers but forms homotrimers in stressed cells?

Answer 27

HSF1

Question 28

in HSF1, trimers are activated and translocate to the nucleus where they bind to what?

Answer 28

HSE

Question 29

name the 4 types of signalling proteins which Hsp70 and 90 interact with?

Answer 29

nuclear hormone receptors, protein kinases, cell cycle regulators, cell death regulators

Question 30

which Hsp regulates glucocorticoid receptor signalling?

Answer 30

Hsp90

Question 31

does the HSF1 transcriptional response and therefore heat shock response decline with age?

Answer 31

yes

Question 32

what is the name of the hypothesis in which an increase in misfolded proteins and a decrease in available chaperones causes defects in signal transduction and immune function?

Answer 32

chaperone overload hypothesis