Zaidi- Protein Processing

Question 1

What is the cytoplasmic pathway?

Answer 1

Used for proteins destined for cytosol, mitochondria, nucleus, peroxisomes. Ends on free ribosomes

Question 2

What is the secretory pathway?

Answer 2

Used for proteins destined for ER, lysosomes, plasma membranes & secretion. Ends on ribosomes sent to ER.

Question 3

What is the ER lumen’s proteins for signal sequences in secretory pathway?

Answer 3

KDEL (Lysine, aspartic acid, glutamic acid, leucine)

Question 4

What is the lysosome’s proteins for signal sequences in secretory pathway?

Answer 4

Mannose 6 phosphate (M6P)

Question 5

What is the membrane’s proteins for signal sequences in secretory pathway?

Answer 5

N terminal apolar sequences

Question 6

What is the secretory’s proteins for signal sequences in secretory pathway?

Answer 6

Trytophan rich domains

Question 7

Where is the secretory pathway localized and what are its two properties?

Answer 7

15-60 AAs localized at N terminus of protein
Two properties:
1-2 basic AAs (Lys/Arg) followed by an extremely hydrophobic sequence

Question 8

What is inclusion cell disease?

Answer 8

Lysosomal proteins not tagged with M6P. Defective or missing GlcNAc phosphotransferase, an enzyme that adds M6P to lysosomal hydrolases. Enzymes are not phosphorylated

Question 9

Name a chaperonin and chaperone?

Answer 9

Chaperonin: HSP60
Chaperone: HSP70

Question 10

What residues are affected by acetylation?

Answer 10

Lys

Question 11

What residues are affected by glycosylation (O and N)?

Answer 11

O: Ser, Thr
N: Asn, Gln

Question 12

What residues are affected by phosphorylation?

Answer 12

Ser, Tyr, Thr, also Asp, His

Question 13

What residues are affected by disulfide bonds?

Answer 13

Cys

Question 14

What is Parknison’s Disease?

Answer 14

Rigidity/stiffness of the limbs and trunk. Tremors. Balance, speech, coordination

Question 15

What causes PD?

Answer 15

Selective loss of dopaminergic neurons (diminished substantia nigra). Aggregation of a-synuclein (AS). Deposits as Lewy bodies in dopaminergic neurons in substania nigra. Symptoms are due to reduced availability of dopamine

Question 16

What is Alzheimer’s Disease?

Answer 16

Most common neurodegenerative, memory loss, misplacing things, confusion, trouble understanding spatial and visual images, changes in mood/personality

Question 17

What causes AD?

Answer 17

Peptide called amyloid beta peptide (AB) is generated and released into EC space) Neurofibrillary tangles

Question 18

What is Huntington’s Disease?

Answer 18

Progressive, Mutation in Huntington gene, this gene protects neurons from apoptosis, repairing damaged DNA

Question 19

What causes Huntington’s Disease?

Answer 19

CAG triplet repeats leads to HD, polyglutamine repeats, selective death of neurons causes the symptoms

Question 20

What is Amyotrophic Lateral Sclerosis (ALS)?

Answer 20

Affects nerve cells in brain/spinal cord causing loss of muscle control, Lou Gehrig’s disease, muscle twitching & weakness in a limb or slurred speech

Question 21

Wha causes ALS?

Answer 21

Mutations in Copper Zinc superoxide dismutase (CuZn SOD). Mutations in SOD causes gain of function. Cytosolic enzyme responsible for dismutation of superoxide anion