ECM 2

Question 1

Multi-adhesive definition

Answer 1

multifunctional as different regions of the molecule can bind to different molecules

Question 2

Laminin Structure

Answer 2

• 3 chains (alpha, beta, gamma)
• form a cross-shaped molecule
• very large and multi-adhesive
• interact with surface receptors
• globular region at N terminus
• coiled-coil domain with all 3 chains

Question 3

Congenital Muscular Dystrophy Cause

Answer 3

• absense of alpha 2 chain in laminin 2.

- hypotonia, generalised weakness and deformities of the joints

Question 4

Firbonectin Info

Answer 4

• not in basal membranes
• exists as eithr insoluble fibrillar matrix or soluble plasma protein
• derived by one gene
• multi adhesive and large
• forms mechanical continuum with actin cytoskeleton in some cell types

Question 5

Fibronectin Function

Answer 5

• regulating cell adhesion and migration in embryogenesis and tissue repair
• important in wound healing (promotes clotting)

Question 6

Fibronectin Structure

Answer 6

• dimer
• two units connected via disulphide bridge
• linked to actins via integrin on cell surface
• integrins bind to fibronectin via RGD molecules

Question 7

Proteoglycan Structure

Answer 7

• core protein which glycosaminoglycan chains (GAG) are covalently attached to.
• GAGs are long, unbranched sugars of repeating disaccharide
• GAGs form hydrated gels for compression

Question 8

Main GAG groups

Answer 8

• Hyaluron
• Chondroitin Sulfate/Dermatan Sulfate
• Heparan Sulfate
• Keratan SUlfate

Question 9

Hyaluron Features

Answer 9

• No core protein (only carb chain)
• synthesised in cell surface
• unsulfated
• Huge molecule

Question 10

GAG to core protein connection ?

Answer 10

Via a link tetrasaccharide

Question 11

Decorin Features

Answer 11

• small proteoglycan
• binds to collagen fibres
• regulates collagen fibre size and arrangement

Question 12

Hyaline Cartilage features

Answer 12

• most abundant cartilage(nose, trachea, bronchi, rib ends, long bone ends)
• aggrecan rich (cushioning effect)

Question 13

Aggrecan Structure

Answer 13

• core protein linked to hyaluronan
• forms complex and has a link protein so very large
• Aggrecan aggregates = aggrecan + hyaluronan + link protein

Question 14

Aggrecan + Cartialge Function??

Answer 14

• GAGs highly sulfated with many carboxyl groups, therefore highly -ve.
  This attracts cations so a large amount of water is retained to form a gel which can be compressed