Week 4 - Common Signalling Pathways

Question 1

Why is cancer and development linked?

Answer 1

They both utilise the same signalling processes/there are processes common to both.

Question 2

State the 5 developmental signalling pathways.

Answer 2

1. Wnt
2. Notch
3. Hedgehog
4. TGF-β
5. FGF

Question 3

What is a morphogen?

Answer 3

A chemical that causes/induces morphological structure formation.

Question 4

What is the need for the 5 developmental signalling pathways?

Answer 4

They are major molecular mechanisms that control embryonic development.

Question 5

List the receptors and ligands involved in the TGF-β signal pathway, and describe the mechanism.

Answer 5

Receptors:
Type I and II single pass transmembrane receptor kinases

Ligands:
Transforming growth factor beta (TGF-β) superfamily including TGF-β, activins, Nodal, Bone Morphogenic Proteins (BMPs), myostatin

Mechanism:
TGF-β ligands bind to a type II receptor, which recruits and phosphorylates a type I receptor. The type I receptor
phosphorylates Smad2/3, which can now bind the Smad4. This Smad2/3/4 complex enters the nucleus where they induce gene expression by binding to a DNA sequence (CAGAC) in the promoters of target genes