L8: Intracellular signalling

Question 1

Steroid hormone receptors

Answer 1

• receptor in cytoplasm
• no receptor = no response

Question 2

steroid-hormone receptor complex

Answer 2

binds to DNA - usually unlocks gene transcription = primary response, goes on to unlock other genes = secondary response

Question 3

how do thyroid hormones get into the cell?

Answer 3

• T3 and T4
• can freely cross membrane, but also lots of channels to facilitate further uptake
  
  • aka they do both :))

Question 4

Gi vs Gs

Answer 4

Gi if things downstream are inhibitory
- inhibition of some things
- channels, gene transcription for channel
Gs if things downstream are stimulatory

Downstream steps determines if Gs or Gi, not the actual protein

Question 5

Adenalyse cyclase

Answer 5

catalyse ATP to cAMP -> cAMP activates PKA, or PKC (which phosphorylate things and activate them)

Question 6

Gq receptor signalling cascade

Answer 6

• associated with phospholipase C on (in membrane) → diacylglycerol → other secondary messangers (PIP2 → IP3 + DAG)
  
  • IP3 opens Ca channels → turns on cell responses
    
    • Ca basically another 2ndary messenger
  • DAG activates PKC