22_ECM Flashcards Preview

BIOL 331 > 22_ECM > Flashcards

Flashcards in 22_ECM Deck (24)
1

What is the function of the glycocalyx? What is it composed of?

Composed of carbohydrate projections extending from integral membrane proteins.

Functions:
- cell-cell/ cell-substratum interactions
- mechanical protection/ barrier

2

What is present in the EC space between intestinal villi to provide mechanical space?

Glycocalyx

3

What is the innermost layer of the EC space?

Glycocalyx

4

Chondrocytes have a (large/small) ECM.

large

5

How many subunits does an integrin possess?

two (alpha & beta)

6

Integrin involvement in cell survival signalling is an example of (outside-in/inside-out) signalling.

outside-in

7

Activation and extension of integrins in neutrophil trapping in an example of (inside-out/outside-in) signalling.

inside-in
(PAF--> GPCR on neutrophil --> neutrophil activation)

8

What is talin? What protein does it activate?

talin indirectly links integrins to the actin cytoskeleton
It is involved in activation of integrins

9

What peptide sequence is present in many integrin substrates? What are some examples of proteins that possess this sequence?

RGD sequence

proteoglycans, fibronectin, laminin, collagen, etc.

10

Which glycoprotein is present solely in the ECM?

collagen

11

What are some cells that produce collagen?

fibroblasts in dermis, epithelial cells, smooth muscle cells

12

Describe the protein structure of collagen. (2˙ structure elements, #of subunits)

3 alpha chains

13

How are the layers of collagen in the corneal stroma arranged?

uniform alternating layers to provide strength and maintain transparency

14

In proteoglycans, core proteins carry (covalently/ionically) attached GAGs, which have a (-/+/neutral) charge.

covalently
negative

15

How do proteoglycans form a porous, hydrated gel? What is the benefit of this gel?

by binding large numbers of cations and water molecules
Resistance to crushing/compression

16

Which proteins provide a scaffold for proteoglycans in the ECM?

collagens

17

In a proteoglycan complex, what molecules make up the central core?

hyaluronic acid

18

Fibronectins are composed of 2 proteins; how are they joined?

disulfide bridges

19

What role do fibronectins play during embryogenesis?

provide pathways for migrating cells

20

Why do cells die when they move off fibronectin?

integrins can't bind their appropriate substrate; there is no survival signal; cells die.

21

Which ECM is a cross-shaped trimer joined by disulfide bonds?

laminin

22

Which two ECM proteins act as pathways/guides for migration?

fibronectin & laminin

23

Which dimeric ECM protein is highly interactive and has many binding sites for other ECM proteins?

Fibronectin

24

Which EMC proteins are trimers?

collagen & Laminin