Extracellular Matrix & Cell Adhesion Flashcards
What body parts made up of type I collagen
tendons
Organs
Skin
Bones
Connective tissue
Teeth
What body parts made up of type II collagen
Cartilage
What body parts made up of type III collagen
Muscles
Arteries
Reticular fibres
Collagen III- found mainly in reticular fibres ( fine fibrous connective tissue occurring in networks to make up the supporting tissue of many organs).
What is made up of type IV collagen
The basal lamina (a network of the extra cellular matrix)
What body parts made up of type V collagen
Bone matrix
Cornea
What is the macromolecular network of the ECM composed of
Collagens
Elastin
Glycoproteins
Proteoglycans
What do the ECM macromolecules form in which cells thrive
Macromolecules of ECM form a 3D gelatinous bed in which cells thrive
What are the 2 types of collagen
Fibrillar (fibril forming)
Non-fibrillary
Give 2 examples of Fibrillar collagens
Type I & type II collagen
What is a Fibrillar collagen, where is it found and what doe they provide
A Fibrillar collagen is a fibril forming collagen
They are major component in tendons, ligaments, skin
They provide HIGH TENSILE STRENGTH
Give 2 examples of non-Fibrillary collagens
Type IV & type VI
What is a non-fibrillary collagen, where is it found and what doe they provide
A non-fibrillary collagen is one that doesn’t form fibrils
They form MICROFIBRILS or mesh like structures
They are structural component of basement membranes
They provide anchorage for cells and filtration
Describe the structure of collagen and why it is strong
Triple helical structure formed by 3 peptide chains
- every 3rd amino acid is glycine. Glycine is the smallest amino acid which means it allows alpha helices to wrap around as they’re so small. These form tight fibril
- Gly-X-Y (proline-hydroxyproline
What is osteogenesis imperfecta and it’s cause
Brittle bone disorder, congenital
Caused by genetic defects in collagen I synthesis
What is osteogenesis imperfecta characterised by
Fragile bones
Thin skin
Thin sclera of eye (whites of eye look blue almost)
Abnormal teeth
Weak tendons
cause:
80%–90% of Osteogenesisimperfecta cases are caused by autosomal dominant mutations in the type 1 collagen genes, COL1A1 and COL1A2. Mutations in one or the other of these genes cause the body to make either abnormally formed collagen or too little collagen.
Describe the specific single base change mutation (substitution) in osteogenesis imperfecta
Single base change mutations converts glycine to a bulky amino acid instead
This prevents the correct folding of collagen chains to form fibrils
What is the more severe type of osteogenesis imperfecta and why do babies usually not survive
Type II osteogenesis imperfecta, dominant if affected individuals survive
Babies usually die at birth as born with too many broken bones
What is elastin found in?
Blood vessels 🩸
Ligaments
Lungs 🫁
Skin
Tendons
Both elastin and collagen are rich in what 2 amino acids
Glycine and proline
What amino acid does elastin have more of and why does this give it elasticity
Elastin has more VALINE (than collagen) which interacts with hydrophobic domains giving it elasticity
Elastin fibres are usually covered by which glycoprotein + why is it important
Elastin fibres usually covered by glycoprotein FIBRILLIN — this coats elastic fibres & restricts the stretch of elastin as we don’t want too much stretch
What is Marfan syndrome causes by
Marfan syndrome is a rare connective tissue disorder (1 in 10k)
Mutations in FIBRILLIN gene — if fibrillin is absent or midfielded this leads to changes in ECM properties
Marfan syndrome characteristics
•tall stature/ long arms/legs
•arachnodactyly (spider fingers)
•loose joints
•floppy cardiac valves
•eye problems (lens dislocation)
•aortic aneurysms
In Marfan syndrome, which growth factor is not bound with extracellular matrix (ECM)
TGF- beta is not bound to ECM : accumulates in lungs and heart instead which changes ECM of organs where there’s a lot of elastic fibres
Why must we regulate growth factors
They can lead to CANCER
