Extracellular Matrix and Proteoglycans- Reynolds Flashcards

1
Q

What is the function of the ECM?

A

provides shape, lubrication, cushioning, anchoring, and allows communication

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2
Q

What is collagen and its structure?

A

it is the major protein component (30%)
left handed matrix as a single strand, right handed matrix as a triple strand
triple strand structure called tropocollagen

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3
Q

What is fibrillar collagen and where is it located?

A

It is a mixture of different overlapping collagen

Gives strength to skin, tendons, and ligaments

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4
Q

What is non-fibrillar collagen?

A

It interacts with fibrillar collagen and makes “mesh-like” structures

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5
Q

Where is collagen synthesized?

A

In the ER

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6
Q

How many amino acids are there in one turn of collagen protein?

A

3 amino acids (Gly-X-Y)
Usually X is a proline and Y is a hydroxyproline
disulfide linkages triggers the triple helix form

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7
Q

What is scurvy?

A

It is a vitamin C deficiency

Vitamin C is needed for synthesizing hydroxyproline in the collagen structure

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8
Q

What is Brittle Bone Disease?

A

Aka: osteogenesis imperfecta
Defect in type 1 collagen
usually from a point mutation

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9
Q

What is desmosine?

A

It is the 2D latticework that elastin creates that allows stretch

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10
Q

Where can you find elastin?

A

vessels, lungs, ligaments, and skin

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11
Q

What is fibronectin?

A

It is an ECM protein that acts as an anchor point
Has many different isomers
tissue specific
involved in cell adhesion, cell migration, embryonic morphogenesis, cytoskeleton, ECM organization

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12
Q

What are proteoglycans?

A

Proteins with large amounts of carbohydrates (GAGs)

Sugars are polyanionic because of uronic acid

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13
Q

Where are proteoglycans made?

A

Golgi complex

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14
Q

What are the functions of proteoglycans?

A

structural support, prevents compression in tissues, con interact to create aggregans, binds to numerous cations to neutralize, allows torsion and shock

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15
Q

As far as proteoglycans:

What is hyaluronic acid?

A

doesnt have a protein core or sufination
longest polysaccharide chain
component in vitreous and synovial fluid

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16
Q

As far as proteoglycans:

what is chondroitin sulfate?

A

most common GAG

major component of cartilage

17
Q

As far as proteoglycans:

what is dermantan sulfate?

A

increases charge density

similar to chondroitin

18
Q

As far as proteoglycans:

what is heparan sulfate?

A

most highly charged
major component of the basement membrane
binds to many soluble regulation proteins

19
Q

As far as proteoglycans:

What is keratan sulfate?

A

most heterogenous

most diverse

20
Q

What are MMPs? (matrix metalloproteases)

A

They digest structural components of ECM

Usually activated to remodel ECM

21
Q

What is the structure of MMPs?

A

Depends on zinc (metalloprotease)
synthesized as a zymogen
abolished by EDTA
3 domains: propeptide, catalytic, haemopexin (which is sometimes absent)

22
Q

How are MMPs activated and used?

A

propeptide domain must be removed
cysteine switch binds to zinc and prevents use by enzyme
The enzyme when activated uses the zinc molecule to activate water, which then can react with the amide bond of the protein substrate

23
Q

What are integrins?

A

cell receptors linking ECM to cytoskeleton

dimer

24
Q

What are cytokines?

A

they manage responses
include inflammatory responses like interleukins and interferons
can signal MMPs for remodeling

25
Q

What are the four types of signaling in the ECM?

A

integrins, ionic changes, cytokines, GF