RTKs

Question 1

GTPases

Answer 1

• switches
• GEF triggeres exchange
• intrinsic GTPase activity
  GAP speed up GTPase activity
  -

Ras
- EGF receptor binds Grb2
- binds SOS1 (GEF)
- converts Ras-GDP to Ras-GTP

Question 2

MAPK cascade

Answer 2

• Ras-GTP activates Raf (MKKK)
• Raf activates MEK on 2 serine residues (MKK)
• MEK phosphrylates T&Y (dual specificty) on ERK (MK)
• ERK1/2 proline directed Ser/Thr kinases

for purpose of signal amplifiaciton

Raf anchored with membrane

there are 5 differenct signalling modules
- there can be unintented cross communication between cascades
- this is mitigated by scaffolding immobilising kinases
- this increases effiecency but reduces amplification

Question 3

PI3-kinase signalling - IGF

Question 4

RTK case studies

Answer 4

• EGF - epidermal growth factor
• IGF - insulin like growth factor