Protein Degradation

Question 1

Lysosomes

Answer 1

Single membrane organelle, contains acid hydrolases. Have proton pumps and LAMPs for autophagy

Question 2

3 types of lysosome

Answer 2

Primary
Secondary
Residual bodies

Question 3

Lysosome formation

Answer 3

Enzymes Made in RER, processed in cis golgi (acquire M6P), accumulate in trans golgi. Vesicate, fuse with late endosome. M6P recycled back with retromer.

Question 4

Lysosome function

Answer 4

Degrade things from late endosomes. Degrade phagosomes. Degrade old organelles.

Question 5

Autophagy types

Answer 5

Macro, controlled by ATG.

Chaperone mediated- LAMP2, for long lived proteins.

Question 6

L-iduronidase

Answer 6

Enzyme for recycling of glycosaminoglycans(connective tissue)

Question 7

Proteasomes

Answer 7

Wood chipper. Uses 1% cell protein. Over 1000 gene products. Needs ATP, and polyubiquitination

Question 8

Proteasome structure

Answer 8

1 core, two caps. Top cap recognizes and unfolds, active sites of degrading enzymes in core.

Question 9

Ubiquitin ligase steps

Answer 9

E1 activates ubiquitin, binding it to E2. E2 gives to E3, which finds and polyubiquitinates protein.

Question 10

Proteasome function

Answer 10

Degrade short lived proteins, repair errors in translation, degrade cyclins, misfolded proteins, activate transcriptional regulators