Week 5 - Nuclear Receptors

Question 1

What are nuclear receptors?

Answer 1

• proteins in the nucleus or cytoplasm
• usually ligand dependent
• causing conformational change
• altered transcriptional programmes

Question 2

What are the regions in a nuclear receptor?

Answer 2

A/B
- N-terminal domain
- least conserved
C
- DBD domain
- most conserved
D
- hinge region
- relation between regions C & E
E
- C-terminal domain
- ligand binding domain

Question 3

What is the zinc finger?

Answer 3

• zinc molecule in C domain
• 4 cystines holding it together
• by electrostatic attraction
• forms P box in helix 1
• forms D box in helix 2
• D box stabilises dimerisation

Question 4

How does the E domain work?

Answer 4

• helix 12 contains ring A
• double bonded oxygen at the end
• attracted to ligand binding pocket
• enters it
• creates AF2 (Activation Function 2) upon agonist binding
• space between helixes 3, 4, 12

Question 5

What are the site arrangements for the classes of nuclear receptors?

Answer 5

• homodimers have inverted repeat
• AGAACA(N₃)TGTTCT
• heterodimers have direct repeats
• AGGTCA(N_1-5)AGGTCA
• monomers have one sequence