Cell Adhesion and Extracellular Matrix

Question 1

What is connective tissue composed of?

Answer 1

cells (scattered)
Extracellular matrix
-fibrillar proteins
-hydrated gel of GAGs

Question 2

Name me some Fibrillar proteins found in the extra cellular matrix

Answer 2

collagen
elastin
fibronectin
laminin

Question 3

Name a vesicle that transports proteins from the RER to the Golgi

Answer 3

COPII buds

Question 4

Tell me about the secretion of collagen

Answer 4

occurs by exocytosis at specialised sites

Question 5

what is the production of collagen fibril by fibroblasts in a membrane tube called

Answer 5

fibripositor

Question 6

elastic recoil is what kind of effect

Answer 6

hydrophobic

Question 7

What do proteoglycans provide

Answer 7

matrix support/cushioning/hydration
glue-like function
Links between proteins of ECM and ECM and cell surface

Question 8

what are GAGS

Answer 8

Long chains of repeating disaccharide units 
highly charged (-ve) and highly hydrated

Question 9

The binding

Answer 9

Extracellular = collagen, fibronectin, proteoglycans
plasma membrane = integrin
intracellular = actin and adapter protein

Question 10

What are the two functions of a myofibroblast

Answer 10

secrete collagen

smooth muscle like synthesise actin myosin and desmin

Question 11

What do myofibroblasts do in response to tissue damage

Answer 11

proliferate
secrete collagen as a scaffold
consolidate damaged area - fibrous scar
contract (reduce size of damaged area)

Question 12

What is the composition of mast cells in terms of granules

Answer 12

heparin

histamine

Question 13

desmosome

Answer 13

intermediate filaments

Question 14

adhernens junction

Answer 14

actin filaments

Question 15

What does plaque contain

Answer 15

desmoplakin

plakoglobin

Question 16

Cadherins

Answer 16

a type of cell adhesion molecule (CAM) that is important in the formation of adherens junctions to bind cells with each other

Question 17

what’s the role of focal adhesions

Answer 17

link the outside of the cell (ECM) through transmembrane proteins (interns) with cytoskeleton (actin filaments)
-signalling platforms

Question 18

hemidesmosomes

Answer 18

the same except intermediate filaments and they are more stable

Question 19

interns

Answer 19

bridges between cyctol and ECM

Question 20

Duchenne muscular dystrophy

Answer 20

gene mutation absence of dystrophin (adapter) due to premature termination of translation

Question 21

PTC 124 (ataluren)

Answer 21

experimental drug which overrides the premature stop signal mutation to produce normal dystrophin

Question 22

E-cadherin

Answer 22

epithelia

Question 23

N-cadherin

Answer 23

neurons and heart muscle

Question 24

P-cadherins

Answer 24

placenta, epidermis

Question 25

VE-cadherin

Answer 25

endothelial

Question 26

Cell adhesion in cancer stages

Answer 26

tumour cells accumulate
carcinoma arriving
cells undergo mesenchymal transition (losing cell adhesion)

Question 27

Microinvasion

Answer 27

• cells convert to “mesenchymal” cells and expression of cadherins reduced
• aided by actin based protrusions (invadipodia)
• basement membrane breached
• in invading tumours leading cells express integrins promoting interaction with ECM and non-epithelial cells during movement