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Flashcards in Extracellular matrix (complete) Deck (147)
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1

What is the extracellular matrix

The interstitial fluid that contains ions, proteins, proteoglycans, and signaling molecules

2

What are the two main components of the extracellular matrix

proteins and proteoglycans

3

What are the three main proteins in the extracellular matrix

1. collagen
2. fibronectin
3. elastin

4

What are the five main proteoglycans found in the extracellular matrix

1. hyaluronic Acid
2. Chondroitin sulfate
3. Dermatan sulfate
4. Heparan sulfate
5. Keratan sulfate

5

What are the four main functions of the proteins and proteoglycans of the extracellular matrix

1. provide shape and structure to the interstitial space
2. lubrication and cushioning of cells and other things
3. provides an anchor point for cellular adhesion
4. allows communication between cells
5. controls cell life cyles (proliferation, differentiation, apoptosis, migration, etc)

6

What do the proteins of the Extracellular matrix provide

Structure and allow cellular adhesion

7

Do proteins or proteoglycans prevent compression of the ECM (extracellular matrix)

Proteoglycans

8

what is the major protein of the ECM

collagen

9

What are proteoglycans

highly charged protein/saccharide polymers that are 95% carbohydrates

10

What is the specific structure of collagen

1. forms a left-handed helix
2. 3 amino acids per turn
3. each turn has the sequence Gly-X-Y
4. Three helical collagen proteins come together to make a triple stranded, right handed superhelix

11

What type of helix does a strand of collagen form

a left handed helix

12

how many amino acids per turn are there in collagen

3

13

what is the specific sequence of amino acids that is found in collagen

Gly-X-Y
X = proline (usually)
Y = hydroxyproline (usually)

14

What is the quaternary structure of collagen

a triple-stranded right handed superhelix

15

Where are the glycine residues of a collagen strand located in the triple helix

toward the center of the triple helix

16

why are the glycine residues of a collagen strand situated toward the center of the triple helix

because of their very small side chain

17

Why are proline and hydroxyproline used with glycine in a collagen strand

they provide strength to the collagen structure due to their bulk and rigidity

18

What are the two classes of collagen

fibrillar (fibril-forming) and nonfibrillar

19

What is the most common type of collagen in the body

Type 1

20

Can collagen fibers be a mixture of collagen types

yes

21

What is the main function of fibrillar collagen

provide tensile strength to skin, tendons, and ligaments

22

What are three types of nonfibrillar collagen

1. basement membrane collagen (type 4)
2. fibril-associated collagens with interrupted triple helices (FACITs)
3. Multiplexins

23

What happens when nonfibrillar collagen interacts with fibrillar collagen

they produce network, or mesh like structures

24

What type of collagen is the primary structure of the basement membrane

type 4 collagen

25

What is the main function of the basement membrane

to prevent migration of certain cell types between different tissue types

26

What are the steps of collagen synthesis

1. Preprocollagen is synthesized with a signal sequence and is directed to the lumen of the ER
2. Signal sequence is removed to make Procollagen
3. Post translational modifications occur
- proline --> hydroxyproline
- sugars are attached to the protein
- Disulfide linkages are incorporated
4. Disulfide linkages trigger formation of triple helical structure
5. tropocollagen then moves to the golgi and is exocytosed
6. tropocollagen is converted into mature collagen
7. mature collagen can be crosslinked to form insoluble collagen fibrils

27

What occurs in converting preprocollagen into procollagen

the signal sequence is removed

28

what post-translational modifications are made to precollagen

1. prolines are converted to hydroxyprolines
2. sugars are attached to the protein
3. disulfide linkages are incorporated

29

What is scurvy

a defect in collagen synthesis that is caused by insufficient vitamin C

30

How does low vitamin C lead to defective collagen synthesis

Vitamin C is a cofactor for the enzymes that produce hydroxyproline, without vitamin C hydroxyproline isn't made