extra cellular matrix

Question 1

what does the ECM control?

Answer 1

migration of cells
tissue integrity and cell shape
proliferation
differentiation

Question 2

what is the matrix made up of?

Answer 2

fibrous proteins - collagen and elastin
adhesion proteins - fibronectin, laminin
hydrated macromolecules - glycosaminoglycans, proteoglycans

Question 3

describe collagen structure

Answer 3

three alpha chains that self assemble into a triple helix, glycine-proline-hydroxyproline

Question 4

describe collagen synthesis

Answer 4

ribosomes produce the chains, the rest is self assembly, vitamin c is a cofactor for the enzyme that adds OH to the proline.

Question 5

describe elastin

Answer 5

elastin can stretch and relax due to single cross links, stretchable but can return to original shape due to the cross links not breaking.

Question 6

what does fibrillin do?

Answer 6

its structural, provides scaffolding (e.g. elastin coats it)

Question 7

what are GAGs and what do they do?

Answer 7

bit of sugar and proteins - protein chain with connected disaccharide
very negatively charged, making them sticky

Question 8

give an example of a GAG and what it does

Answer 8

hyaluronan complex
absolutely massive
super charged so brilliant at holding water and creating space - important in eye formation

Question 9

basal body?

Answer 9

the base of the axoneme, attaches the flagella/cilia to the cell

Question 10

what is the fibronectin structure like, and what does it do?

Answer 10

has disulphide bridges for strong cross links
has collagen binding sites, so can add the ability of cohesion to collagen binding sites, as the fibronectin has charged ‘sticky’ residues to bind to cells.

Question 11

how does integrin bind to the cell on one side, and the matrix on the other?

Answer 11

divalent cations for strong ionic binds to the matrix
binds indirectly via talin to the cytoskeleton.