Miles - Protein Synthesis II: Folding, Processing, ER

Question 1

Chaperones

Answer 1

Help mediate proper folding

Question 2

Hsp70

Answer 2

ATP-dependent

Binds and covers hydrophobic patches to protect from misfolding or clumping

Question 3

Protein disulfide isomerase

Answer 3

Cystine bridges

Question 4

Peptidyl Prolyl Isomerase

Answer 4

Convert trans-cis changes in peptide bonds

Question 5

What occurs to the initiator MET?

What terminus does this occur at?

Answer 5

It is removed via proteolysis from the N-terminus

Question 6

What allows proteins to be targeted for transport to specific locations?

Answer 6

N-terminal signal sequences

Question 7

Glycosylation

Answer 7

Occurs in ER, N-linked occurs on asparagine residues during cotranslational translocation into ER

Question 8

Calnexin and Calreticulin

Answer 8

Binds N-linked residue site when one glucose remains, prevents last removal

Folding sensor examines protein, adds glucose back if not properly folded

Question 9

GPI Anchors

Answer 9

Attach proteins to the luminal side of the ER membrane

Question 10

N-myristoylation

Answer 10

Myristic acid attached to N-terminal glycine residue–cytostolic can impair plasma membrane embedding

Question 11

Prenylation

Answer 11

Addition of lipid

Prenyl group attached to C-terminal cysteine residue

Question 12

Palmitoylation

Answer 12

Addition of lipid

Palmitic acid attached to internal cysteine residue

Question 13

What AAs are the targets for phosphorylation?

Answer 13

Serine
Threonine
Tyrosine

Question 14

Nitrosylation

Answer 14

Addition of NO groups to internal cysteine

Question 15

Unfolded Protein Response (UFR)

Answer 15

Excess of unfolded proteins activate UFR pathway.

Leads to expansion of ER, + chaperones, and apoptosis if shit gets really bad

Question 16

Degradation of Proteins

Answer 16

Ubiquitin attached to side chain of lysine residue, targets protein for degradation. The more ubiquitation = more likely to be degraded.

Question 17

Prion Disorders

Answer 17

You know these..

Infection with misfolded protein stimulates other proteins to misfold

Question 18

Alzheimer’s

Answer 18

Amyloid plaques, similar to prion derived

Question 19

Alpha-1 Antitrypsin Disorder

Answer 19

Defect of a protease inhibitor, emphysemes, smoking makes worse for heterozygotes