1.13 ECM I - GAG's and Proteoglycans Flashcards Preview

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Flashcards in 1.13 ECM I - GAG's and Proteoglycans Deck (21):
0

What is the Extracellular Matrix?

Non Cellular component within all tissues and organs.

1

The ECM is composed of what three things?

Water
Proteins
Polysaccharides

2

What is major component of ECM

Water

3

What are the three classes of molecules found in the Extracellular Matrix

Glycoproteins
Glycosaminoglycans (GAGs)
Proteoglycans

4

What is the ground substance?

The space between the cells and fibers

5

What is a Glycosaminoglycan (GAG)?

unbranched repeating disaccharides containing an amino sugar

6

List the four classes of glycoaminoglycans

Hyaluronan
Keratan Sulfate
Chondroiton Sulfate
Heparan Sulfate

7

Which of the GAGs does not carry a Sulfate

Hyaluronan

8

What causes GAGs to bring water into the matrix?

High density negative charges attract sodium and bring water into matrix

9

What is the chief function of GAGs

To maintain proper homeostatic environment for cells and fibrous elements

10

What is a Proteoglycan?

One or more GAGs are COVALENTLY joined to a membrane or secreted protein

11

T or F, Hyaluronic Acid does not form Proteoglycans?

True

12

What are the three classes of Proteoglycans?

Small Leucine-Rich Proteoglycans (SLRPs)
Modular Proteoglycans
Cell Surface Proteoglycans

13

What is the major structural proteoglycan found in cartliage?

Aggrecan

14

T or F, Proteoglycans directly bind to hyaluronan forming giant proteoglycan aggregates

False, They INDIRECTLY bind to Hyaluronan through linker proteins

15

What is a function of Syndecan-1, a proteoglycan?

Binds Chemokines which play a role in inflammation

16

GAGs are covalently linked to the protein core in Proteoglycans. Explain this linkage further

The GAGs are attached via a Serine residue in the core protein.

17

Compare Normal PG catabolism and Abnormal PG catabolism

Normal: Bone replacing cartilage during development
Abnormal: Tumor invasions, arthritis

18

How are Proteoglycans mostly degraded?

Through lysosomes

19

What happens when GAGs can't be broken down?

It is a lysosomal storage disease

20

What two GAGs do not accumulate due to the lysosomal storage deficiency?

Hyaluronate and Chondroiton sulfate because they can be catabolized through other pathways