Hormone Synthesis, Secretion and Transport

Question 1

3 types of coat proteins

Answer 1

Cop 1, Cop II and clathrin

Question 2

Functions of each coat protein

Answer 2

• COP II mediates transfer of vesicles from the rough ER to the cis-Golgi/cis-Golgi network
• COP I mediates retrograde transport from the trans- to the medial – to the cis-Golgi as well as from the cis-Golgi/cis-Golgi network to the rough ER
• Clathrin mediates transfer of vesicles that bud from the trans-Golgi network and the plasma membrane and that then fuse with late endosomes

Question 3

Vesicular secretion (steps 1-6)

Answer 3

1. Sorting hormone for secretion
2. Coat protein association (e.g. COP I retrograde or COP II forward) and vesicle formation
3. Budding and trafficking (v-SNARE/t-SNARE) not random – uses directed receptor recognition
4. Uncoating
5. Docking
6. Fusion to target membrane

Question 4

vesicular secretion is driven by what?

Answer 4

GTP hydrolysis

Question 5

what influences the half-life of mRNA

Answer 5

5” cap and length of 3’ poly A tail

Question 6

are steroids and eicosandoids secreted immediately or inependently

Answer 6

secreted immediately so control at synthesis level - plasma membrane soluble so can easily pass through

Question 7

are peptide hormones secreted immediately or independantly

Answer 7

•synthesis and secretion regulated independently