Signalling pathways relevant to cartilage

Question 1

Which 3 signalling pathways are important in cartilage development?

Answer 1

Wnt signalling

FGF signalling

Question 2

Which Wnt proteins are important in cartilage development?

Answer 2

Wnt 1-8

Question 3

All Wnt proteins have the same functions

TRUE or FALSE

Answer 3

FALSE

All Wnt proteins have slightly different functions

Question 4

What receptor does the Wnt protein bind to?

Answer 4

Frizzled

Question 5

What are the 3 pathways that can be triggered once Wnt binds to its receptor?

Answer 5

Canonical pathway

Non-canonical pathway

Wnt-Ca2+ pathway

Question 6

In which pathway does the LRP5 coreceptor play a role?

Answer 6

Canonical pathway

Question 7

What response does the canonical pathway trigger?

Answer 7

Gene induction - transcription

Question 8

What response does the non-canonical pathway trigger?

Answer 8

Cell movements

Question 9

What is LRP5?

Answer 9

An intracellular transmitter

Large proteins with many domains

Can bind to many molecules

Question 10

The canonical pathway regulates the intracellular concentration of this important protein

Answer 10

B-catenin

Question 11

What is the role of B-catenin in chondrocytes?

Answer 11

Cofactor for transcription factors

B-catenin is constantly broken down by b-TrCP

B-catenin accumulation leads to B-catenin being translocated into nucleus

Here it activates specific gene signalling

Question 12

What triggers accumulation of B-catenin?

Answer 12

Wnt signalling

Question 13

What is the role of GFG signalling?

Answer 13

Induces cell proliferation - p38

Inhibits cell proliferation - ERK and STAT1

Question 14

Relevance of FGF signaling in cartilage formation

Answer 14

In the begining of tissue development there is and increase in FGF to get highly proliferative pool of cells

This is then turned down

Other signal molecules differentiate the mass of tissue into target tissue