Extracellular Matrix

Question 1

What is ECM

Answer 1

Complex network of protein/carb filling space between cells.
Has fibrillation/non-fibrillar components

Question 2

Key function of ECM

Answer 2

Support,
Determine tissue properties,
Growth
Development

Question 3

Types of collagen

Answer 3

Type 1,2,3= fibrillar
Type 4= basement membrane

Question 4

Types of multi-adhesive glycoprotein

Answer 4

-Fibronectin, fibrinogen,
-laminins(basement membrane)

Question 5

Types of proteoglycan

Answer 5

-Aggrecan, versican, decorin
-perlecan(basement membrane)

Question 6

What is collagen

Answer 6

-Fibrous protein.
-In Bone, tendon, skin.
-Most abundant protein in mammals

Question 7

Describe collagen fibres arrangement/triple helix

Answer 7

-3 alpha chains forming triple helix.
- every third position= glycine
Glycine small to fit interior.
-gly-x-y repeat
X=proline
Y=hydroxyproline

Question 8

Type 1 collagen composition

Answer 8

Chains from 2 types of genes:
[a1(I)]2 [a2(I)]

Question 9

Type 2/3 collagen composition

Answer 9

1 chain type:
[a1(II)]3 [a1(III)]3

Question 10

Assembly of collagen fibres

Answer 10

1. Single collagen polypeptide chain
2. 3 alpha chains/procollagen with (C/N-terminal propeptide)
   3.collagen fibril
3. Collagen fibre

Question 11

What causes scurvy and its effect

Answer 11

Vit c deficiency.
Under-hydroxylated (prolyl/Lysyl) collagens- affect it’s stability.

Question 12

What is EDS (Ehlers-Danlos syndrome)

Answer 12

Inherited connect tissue disorder- stretch skin+loose joints.
Mutation in collagen affecting its production, structure, processing.

Question 13

What are fibril-associated collagens

Answer 13

(E.g. type 9/12)- regulates organisation of collagen fibrils

Question 14

Where can excess collagen production be found

Answer 14

Fibrotic disease like:
Alcoholic liver cirrhosis.
Fibrotic lung.

Question 15

What is. Diabetic nephropathy

Answer 15

Accumulation of ECM -> thickened glomerular basement membrane in kidney ->renal failure

Question 16

what is Alpert syndrome

Answer 16

Mutation in type 4 collagen -> abnormally split GBM -> loss of kidney function

Question 17

What is laminin

Answer 17

A/b/y chain with a coiled-coil domain. Cross shaped.
One end= perlecan/integrin/dystroglycan.
A chain end= integrin

Question 18

What is elastic fibres

Answer 18

In skin, blood vessels, lungs.
-Elastin core
-surrounded by microfibrils
-rich in protein fibrillin

Question 19

What is marfan’s syndrome

Answer 19

Fibrillin-1-mutation
Thickening of aorta
Elastic fibres disarray
Individuals predisposed to aortic ruptures

Question 20

What fibronectin do

Answer 20

Disulphide linked.
Cell adhesion, migration, tissue repairs in embryogenesis,
Wound healing, promote blood clotting

Question 21

What are proteoglycan

Answer 21

Core proteins with attached glycosaminoglycan (GAG) chains.

Question 22

what are GAG chains

Answer 22

Repeating disaccharide.
Sulfation/carboxylation increase NEGATIVE charge

Question 23

What are the main GAG varieties

Answer 23

Hyaluronan
Chondroitin/dermatan sulfate
Heparin sulfate
Keratan sulfate

Question 24

What aggrecan do

Answer 24

Resist compressive force
By giving up water and regain when load is reduced
// extra info
Cleaved by aggrecanases/metalloproteinases- cushioning properties of cartilage lost- OA