Cell Adhesion and the Extracellular Matrix

Question 1

Function of fibroblasts?

Answer 1

• synthesises extracellular matrix and collagen, elastin and proteoglycans
• produces structural framework (stroma) for tissues
• plays a role in wound healing

Question 2

Function of myofibroblasts?

Answer 2

between a fibroblast and smooth muscle cell

• secrete collagen (fibroblast like)
• secrete actin, myosin, desmin (smooth muscle like)

Question 3

Function of adipocytes?

Answer 3

(fat cells/ lipocytes) 
make up adipose tissue
- store energy as fat
- insulating (subcutaneous)
- packing/supporting (eye)

Question 4

What does connective tissue consist of?

Answer 4

• cells

- extracellular matrix - fibrillar proteins and hydrated gel of GAGs

Question 5

Extracelular matrix consists of?

Answer 5

• fibrillar proteins

- hydrated gel of GAGs (repeating sugar chain subunits often linked to proteins)

Question 6

Function of proteoglycans?

Answer 6

provide:

• matrix support, cushioning, hydration
• glue like-function
• link between proteins of ECM and ECM and cell surface

Question 7

What are GAGs?

Answer 7

• long chains of repeating disaccharide units
• highly charged (negative)
• highly negative

Question 8

How does the extracellular matrix link to the intracellular cytoskeleton?

Answer 8

collagen/proteoglycans bind fibroconectin that links to interns (in membrane) which themselves bind via adapted to actin skeleton

Question 9

What role do myofibroblasts play in tissue damage?

Answer 9

• proliferate (divide)
• secrete collagen (scaffold)
• make fibrous scar
• contract- reducing size of damaged area

Question 10

What is the function of leptin?

Answer 10

• regulates appetite, food intake and body weight

- absence can cause weight gain

Question 11

What do cell junctions/ adhesion proteins link cells to?

Answer 11

• other cells

- extracellular matrix

Question 12

What molecular defect results in Duchenne’s muscular dystrophy?

Answer 12

gene mutation results in an absence of dystrophin (adapter protein) due to premature termination of translation
- damage to muscle fibre due to muscle tearing

Question 13

What does Duchenne’s muscular dystrophy cause?

Answer 13

muscle wasting and weakness

Question 14

What experimental approaches have been used to stop muscular dystrophy?

Answer 14

• ## drug to override premature stop signal mutation - to produce normal dystrophin - ataluren - resulted in some improvements but not great results