Extracellular Matrix Flashcards
What is ECM
Complex network of protein/carb filling space between cells.
Has fibrillation/non-fibrillar components
Key function of ECM
Support,
Determine tissue properties,
Growth
Development
Types of collagen
Type 1,2,3= fibrillar
Type 4= basement membrane
Types of multi-adhesive glycoprotein
-Fibronectin, fibrinogen,
-laminins(basement membrane)
Types of proteoglycan
-Aggrecan, versican, decorin
-perlecan(basement membrane)
What is collagen
-Fibrous protein.
-In Bone, tendon, skin.
-Most abundant protein in mammals
Describe collagen fibres arrangement/triple helix
-3 alpha chains forming triple helix.
- every third position= glycine
Glycine small to fit interior.
-gly-x-y repeat
X=proline
Y=hydroxyproline
Type 1 collagen composition
Chains from 2 types of genes:
[a1(I)]2 [a2(I)]
Type 2/3 collagen composition
1 chain type:
[a1(II)]3 [a1(III)]3
Assembly of collagen fibres
- Single collagen polypeptide chain
- 3 alpha chains/procollagen with (C/N-terminal propeptide)
3.collagen fibril - Collagen fibre
What causes scurvy and its effect
Vit c deficiency.
Under-hydroxylated (prolyl/Lysyl) collagens- affect it’s stability.
What is EDS (Ehlers-Danlos syndrome)
Inherited connect tissue disorder- stretch skin+loose joints.
Mutation in collagen affecting its production, structure, processing.
What are fibril-associated collagens
(E.g. type 9/12)- regulates organisation of collagen fibrils
Where can excess collagen production be found
Fibrotic disease like:
Alcoholic liver cirrhosis.
Fibrotic lung.
What is. Diabetic nephropathy
Accumulation of ECM -> thickened glomerular basement membrane in kidney ->renal failure
what is Alpert syndrome
Mutation in type 4 collagen -> abnormally split GBM -> loss of kidney function
What is laminin
A/b/y chain with a coiled-coil domain. Cross shaped.
One end= perlecan/integrin/dystroglycan.
A chain end= integrin
What is elastic fibres
In skin, blood vessels, lungs.
-Elastin core
-surrounded by microfibrils
-rich in protein fibrillin
What is marfan’s syndrome
Fibrillin-1-mutation
Thickening of aorta
Elastic fibres disarray
Individuals predisposed to aortic ruptures
What fibronectin do
Disulphide linked.
Cell adhesion, migration, tissue repairs in embryogenesis,
Wound healing, promote blood clotting
What are proteoglycan
Core proteins with attached glycosaminoglycan (GAG) chains.
what are GAG chains
Repeating disaccharide.
Sulfation/carboxylation increase NEGATIVE charge
What are the main GAG varieties
Hyaluronan
Chondroitin/dermatan sulfate
Heparin sulfate
Keratan sulfate
What aggrecan do
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
