L 24

Question 1

What are two examples of protein targeting signals?

Answer 1

1. ER: hydrophobic signal sequence

2. Lysosome: M6P

Question 2

What is the zellweger syndrome?

Where is the defect, what cuases it, what are some consequences

Answer 2

• a protein targeting disease
• Peroxisomal targeting defect, the peroxisomal enzymes accumulate in the cytosol
• neural, cardiovasclar, renal, adrenal dystrophies
• accumulate very long chain fatty acids
• cataracts, glaucoma, retinal detachment
• average lifespan 12 weeks
• no treatment

Question 3

What does NLSs stand for?

Answer 3

Nuclear Localization Signals

Question 4

What does NLS do?

Answer 4

direct proteins to the nucleus

Question 5

What is NPC

Answer 5

nuclear pore complex

Question 6

What does NPC function as?

Answer 6

Entrance to the nucleus for proteins

It is perhaps the largest protein complex in the cell and has more than 30 dif proteins arranged. 50x greater than ribosomes

Question 7

What does the secretory pathway do? Give some examples

Answer 7

it prepares and packages proteins for secretion

i.e hormones
blood albumin
antibodies
snot
digestive enzymes
low density lipoprotein

Question 8

What does the secretory pathway do for the integral membrane proteins?

Answer 8

It also inserts and folds integral membrane proteins.

• ion channels
• nutrient transporters
• hormone receptors
• neurotransmitter receptors
• cell adhesion molecules

Question 9

How does botulism and tetanus neurotoxins block neuronal exocytosis and neurotransmission?

Answer 9

botulism and tetanus neurotoxins destroy SNARE proteins