adhesion molecules (questions in lecture)

Question 1

What are the adhesion molecules that form occluding/tights
junctions?

Answer 1

clauddins and occludins

Question 2

Where are the occluding/tight located?

Answer 2

apical region

Question 3

What do the adhesion molecules recognize on a neighbouring
cell, i.e. what is their ‘ligand’?

Answer 3

Claudins and occulins recognise the same molecules on neighbouring cells
claudins bind claudins on adjacent cells

Question 4

What are molecules associated with the cytoplasmic side of
the adhesion molecules?

Answer 4

ZO proteins link claudins and occulins to actin filaments of cytoskeleton

Question 5

Which cytoskeletal element are tight junctions connected to?

Answer 5

actin filaments

Question 6

What is the main function of tight/occluding junctions ?

Answer 6

form a protective barrier/ diffusion barrier

Question 7

What are the two main anchoring junctions that mediate
adhesion BETWEEN cells?

Answer 7

adheren junctions and desmosomes

Question 8

What are the adhesion molecules that form anchoring junctions?

Answer 8

cadherins and desmosomal cadherins

Question 9

name the desmosomal cadherins

Answer 9

desmoglein
desmocollin

Question 10

What do the adhesion molecules of anchoring junctions recognize on a
neighbouring cell, i.e. what is their ‘ligand’?

Answer 10

adheren junctions recognise catenins (a-catenin, b-catenin p-120)
desmosomes recognise desmoplankin, plankofilin and plankoglobin

Question 11

Which cytoskeletal element are each of these anchoring
junctions connected to?

Answer 11

cadherins bind to actin filaments
desmosomes bind to intermediate filaments (e.g keratin)

Question 12

What is the main function of anchoring junctions ?

Answer 12

Adherens Junctions: Mediate dynamic cell-cell adhesion
desmosomes provide mechanical strength

Question 13

name the integrins

Answer 13

focal adhesions
hemidesmosomes

Question 14

What are the adhesion molecules that form focal
adhesions?

Answer 14

integrins

Question 15

where are focal adhesions located

Answer 15

basal membrane connect cell to ECM

Question 16

What do the adhesion molecules of focal adhesions recognize i.e. what is their
‘ligand’?

Answer 16

extracellular maxtrix proteins:
Fibronectin
Collagen
Laminin
Vitronectin

Question 17

how many subunits are there in focal adhesions

Answer 17

2
a-intergin and b-integrin

Question 18

What are other molecules associated with the cytoplasmic
side of the adhesion molecules (focal adhesions)?

Answer 18

vinculin
talin
focal adhesion kinase

Question 19

Which cytoskeletal element are focal adhesions connected
to?

Answer 19

actin filament

Question 20

what is the main function of focal adhesions

Answer 20

cell-ECM adhesion
cell migration
signal transduction
force transduction

Question 21

What are the adhesion molecules that form hemidesmosomes?

Answer 21

a6B4 integrins

Question 22

where are hemidesmosomes located

Answer 22

basal membrane

Question 23

What do the adhesion molecules of hemidesmosomes recognize i.e. what is their
‘ligand’?

Answer 23

lamins link a6B4 integrins to collagen

Question 24

What are other molecules associated with the cytoplasmic
side of the adhesion molecules (hemidesmosomes)

Answer 24

plectin

Question 25

Which cytoskeletal element are hemidesmosomes connected
to?

Answer 25

intermediate filaments (keratin)

Question 26

main functions of hemidesmosomes

Answer 26

cell-ECM adhesion
cell signalling

Question 27

What is a directly communicating junction?

Answer 27

gap junction

Question 28

What are the adhesion molecules that form gap junctions

Answer 28

connexons (6 connexins)

Question 29

Zonula occludens (ZO) proteins role in gap junctions

Answer 29

These scaffolding proteins help organize connexins within the plasma membrane and can mediate their connection to the cytoskeleton

Question 30

how can calmodulin modulate gap junctions

Answer 30

in response to changes in calcium levels, which can open or close the connexons.