adhesion molecules (questions in lecture) Flashcards

1
Q

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

A

clauddins and occludins

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2
Q

Where are the occluding/tight located?

A

apical region

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3
Q

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

A

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

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4
Q

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

A

ZO proteins link claudins and occulins to actin filaments of cytoskeleton

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5
Q

Which cytoskeletal element are tight junctions connected to?

A

actin filaments

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6
Q

What is the main function of tight/occluding junctions ?

A

form a protective barrier/ diffusion barrier

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7
Q

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

A

adheren junctions and desmosomes

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8
Q

What are the adhesion molecules that form anchoring junctions?

A

cadherins and desmosomal cadherins

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9
Q

name the desmosomal cadherins

A

desmoglein
desmocollin

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10
Q

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

A

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

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11
Q

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

A

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

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12
Q

What is the main function of anchoring junctions ?

A

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

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13
Q

name the integrins

A

focal adhesions
hemidesmosomes

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14
Q

What are the adhesion molecules that form focal
adhesions?

A

integrins

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15
Q

where are focal adhesions located

A

basal membrane connect cell to ECM

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16
Q

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

A

extracellular maxtrix proteins:
Fibronectin
Collagen
Laminin
Vitronectin

17
Q

how many subunits are there in focal adhesions

A

2
a-intergin and b-integrin

18
Q

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

A

vinculin
talin
focal adhesion kinase

19
Q

Which cytoskeletal element are focal adhesions connected
to?

A

actin filament

20
Q

what is the main function of focal adhesions

A

cell-ECM adhesion
cell migration
signal transduction
force transduction

21
Q

What are the adhesion molecules that form hemidesmosomes?

A

a6B4 integrins

22
Q

where are hemidesmosomes located

A

basal membrane

23
Q

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

A

lamins link a6B4 integrins to collagen

24
Q

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

25
Which cytoskeletal element are hemidesmosomes connected to?
intermediate filaments (keratin)
26
main functions of hemidesmosomes
cell-ECM adhesion cell signalling
27
What is a directly communicating junction?
gap junction
28
What are the adhesion molecules that form gap junctions
connexons (6 connexins)
29
Zonula occludens (ZO) proteins role in gap junctions
These scaffolding proteins help organize connexins within the plasma membrane and can mediate their connection to the cytoskeleton
30
how can calmodulin modulate gap junctions
in response to changes in calcium levels, which can open or close the connexons.