10.1 Cell Adhesions

Question 1

What adhesions require calcium?

Answer 1

Integrins, Cadherins, Selectins

Question 2

How do cells adhere?

Answer 2

Through interaction of cell-adheison molecules or CAMs and there are both cell-cell and cell-matrix adhesion molecules

Question 3

Cadherin

Answer 3

• calcium dependent
• Play roles in development and tissue maintenance
• mediate cell-cell attachment by homotypic interaction.

Question 4

E-Cadherin

Answer 4

Epithelial

Question 5

N-Cadherin

Answer 5

neurons, muscles

Question 6

P-Cadherin

Answer 6

placenta, epidermis

Question 7

Cadherins are linked to the actin cytoskeleton by ______ .

Answer 7

catenins

Question 8

Calcium makes Cadherins ____ .

Answer 8

Stiff allowing for attachment to neighboring cells.

Question 9

In the absence of calcium, Cadherins are _____ .

Answer 9

Floppy. Cannot attach to neighboring cells.

Question 10

N-Cadherins must be turned on and off at proper times due to their function in ______ and ______ maintenance.

Answer 10

Development/tissue maintenance

Question 11

N-CAMs

Answer 11

(neurons) – adhesion molecule
- Member of the immunoglobin superfamily forming cation independent links between cells
- required for proper formation of neuromuscular junctions

Question 12

I-CAMs

Answer 12

(endothelial cells) –adhesion molecule

-Member of the immunoglobin superfamily forming cation independent links between cells

Question 13

What is the structure of N-CAMs and I-CAMs?

Answer 13

All have 5 folded immunoglobulin-like extracellular domains which can form homotypic interactions

Question 14

Adhesion may be ______ during development.

Answer 14

down-regulated

Question 15

FAK

Answer 15

Focal Adhesion kinase = recruited to focal adhesions, clustered FAK molecules phosphorylate each other initiating FAK dependent intracellular signaling events

Question 16

Integrins cluster to form ______ .

Answer 16

Focal adhesions

Question 17

What is the structure of an integrin?

Answer 17

Heterodimer with an alpha and beta subunit. They are classified by type of subunit

Question 18

How are WBC recruited to sites of inflammation?

Answer 18

Endothelial cells express E-and P-selectins during inflammation to recruit WBC with L-selectins on them.

Question 19

Selectins

Answer 19

Carbohydrate (sugar)-linking proteins that form calcium dependent cell-cell and cell-substrate adhesions

Question 20

L Selectins

Answer 20

leukoctytes (WBC)

Question 21

P Selectins

Answer 21

Both platelets and endothelial cells

Question 22

E Selectins

Answer 22

endothelial cells