Intro + Collagens

Question 1

What is the ECM

Answer 1

Network of proteins and carboyhdrates filling spaces between cells, with fibrillar (fibre making) and non-fibrillar components

Question 2

4 key functions of ECM?

Answer 2

• Provides physical support
• Determines mechanical and phyicochemical properties of the tissue
• Influnces growth,adhesiom and differentiation status of cells and tissues
• Essential for development, tissue function and organogenesis

Question 3

3 components of the ECM?

Answer 3

• Collagens
• Multi-adhesive glycoproteins (fibrinogen, laminins etc)
• Proteoglycans

Question 4

4 disorders resulting from ECM abormalities?

Answer 4

• Gene mutations affecting matrix proteins
• Gene mutations affecting ECM catabolism
• Fibrotic disorders due to excessive ECM deposition
• Disorders due to excessive loss of ECM

Question 5

How many alpha chains in collagen?

Answer 5

3 to form a triple helix

Question 6

2 characteristics of the collagen triple helix

Answer 6

Glycine-x (often proline)- y (often hydroxyproline) repeat

3 alpha chains form a stiff triple helical structure

Question 7

Assembly of collagen fibre?

Answer 7

1 alpha chain → 3 alpha chains → collagen fibril → collagen fibre

Question 8

Domains in collagen chains?

Answer 8

Non-collagenous domains at N- and C- termini, removed after secretion in fibrillar collegen

Question 9

Lysine and proline hydroxylation?

Answer 9

Requires Fe2+ and vitamin C. Contributes to interchain hydrogen bond formation

Question 10

Which collagens do not form fibrils?

Answer 10

Fibril-associated collagens associated with other collagens and regulate their organisation (types IX and XII)

Type IV collagen is a network-forming collagen and is present in all basement membranes

Question 11

How could you best define type I collagen with the composition [α1(I)]2 [α2(I)]?

Answer 11

A heterotrimer made up of 2 α1(I) chains and one α2(I) chain