Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BMS 242 - Advanced Cell and Molecular > Extracellular matrix integrins and cell migration > Flashcards

Extracellular matrix integrins and cell migration Flashcards

1
Q

Where is extracellular matrix secreted from?

A

Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What components make up the ECM?

A

Laminin
Collegen
Elastin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are fibronectins?

A

Large, secreted proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What domains do fibronectins have?

A
  • Heparin binding domain - interact with cells
  • Collagen binding domain
  • Self-association domain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the structure of laminin?

A

Trimer

Many domains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does laminin interact with at the C terminal domain?

A
  • Intergrins
  • Perlecan
  • Dystroglycan
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the structure of integrins?

A
  • Alpha and beta subunits
  • Each monomer has a single transmembrane domain
  • Alpha subunit is cleaved and held together by disulphide bonds
  • Extracellular cysteine rich domain
  • Matrix binding domain at the amino terminus
  • Intracellular component is anchored to actin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do intergrins interact?

A

Heterodimerically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In integrins, what do extracellular cysteines allow?

A
  • The formation of disulphide bridges

- To interact with different extracellular components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do integrins interact with actin?

A

Using talin and vinculin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the amino terminus of integrins bind to?

What does this result in?

A

The ECM and divalent cations (Ca2+, Mg2+)

Results in activation of the integrin and activates intracellular signalling pathways that influence the behaviour of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many alpha and beta subunits are there of integrins?

How can they bind?

A

18 subtypes

Can be paired in many combinations - to make 24 varients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How are integrins acitvated?

A

In 2 ways:

1) Binding to the ECM
- Causing a conformational change (unfolding of extracellular domain)
- Become activated
- Activate the intracellular domain to bind to talin

2) If integrin interacts with intracellular domain - causes unfolding of the extracellular domain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are FAKs?

A

Focal adhesion kinases

A type of tyrosine kinase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How are FAKs activated?

What do activated FAKs do?

A

Activated by integrin binding to the ECM, on the foramtion of adhesions

When activated - FAK phosphorylates tyrosine residues - docking regions for other proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the typical pathway that actin is polymerised?

A
  • Fibronectin
  • Integrin (extracellular)
  • FAK (in the cytoplasm)
  • Tyrosine phosphorylation (localised in the area of focal adhesion)
  • Actin fibre polymerisation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are focal adhesions?

A
  • Protein complexes where the cell connects to the ECM

- Where mechanical force and regulatory signals are transmitted between the cytoplasm and the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are FAKs involved with?

A
  • MIGRATION (are made and formed)

- ANOIKIS (attachment-dependant cell death)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What do FAKs bind to?

A

The cytosolic tail of integrin, with the assistance of other proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where to integrins cluster to?

What does this trigger?

A

The sites of the matrix contact

This triggers the assembly of cell-matrix junctions (focal adhesions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens to cells if they are not attached to a substrate?

A

They die

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is motility linked with?

A

Adhesion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What forms the basis of cell motility in mammals?

24
Q

What is the leading edge of a cell?

What is present in the leading edge and why?

A

The direction that the cell is moving in

Actin - pushes the cell forwards

25
Where are microtubules present in the cell?
In the centre
26
What are lamellipodium?
Actin projection at the leading edges
27
What happens to focal adhesions as the cell migrates?
The focal adhesions are recycled from the back of the cell to the front
28
What is the actin cortex? What does it provide to the cell?
Skeleton underneath the membrane (surrounding the whole cell) Maintains cell shape as the cell migrates Prevents the cell becoming flat Gives the migrating cell strength
29
How is the migrating cell polarised?
Different things happening at the front and rear: - Recycling of focal adhesions - Flow of actin to the front of the cell
30
What is ruffling of the leading edge and what is it important for?
- Actin polymerisation pushing the membrane up in different directions - Important in sensing guidance cues
31
How is actin attached to the lamellipodia?
At the + end (distal to the cell)
32
What happens at the - end of lemellipodia?
Actin fillaments are removed and recycled to the + end
33
What is cytochalasin B?
A drug which binds to the + end of actin and prevents any further actin polymerisation Can be used to study actin polymerisation
34
What complex is important in actin polymerisation?
The ARP complex
35
What is the structure of the ARP complex?
Made of many proteins (including Arp2 and Arp3)
36
What do Arp2 and Arp3 do?
Nucleate actin monomers by binding at the minus end and allowing actin to polymerise
37
What do Arp2 and Arp3 resemble?
Actin
38
What activates ARP complex activity? How?
Rac kinase - initiates the formation of ARP complexes
39
What is the result of Rac kinase?
Increase in formation of ARP complexes Increase nucleation of actin filaments Drive the leading edge forwards
40
How do ARP complexes form a branched networks? What does this provide to the cell?
ARP complexes can bind to existing actin filaments Provides stability and strength and pushes the leading edge forwards
41
What happens to focal adhesions when the cell migrates?
- Focal adhesions that interact with the ECM at the rear of the cell are broken - Recycled to the leading edge to initiate new binding
42
Where in the migrating cell is stable adhesion?
At the leading edge
43
Where in the migrating cell is sliding adhesion?
At the rear
44
How are focal adhesions different?
They are all made of different molecules Some are stable, whereas some are transient
45
What are the 2 different categories of focal adhesions? What are the differences between the 2?
1) Low density - Found around the leading edge - Immobile (fixed within the cell) 2) High density - Compacted - Found away from the leading edge - Can move within the membrane
46
What are low density focal adhesions?
rac1 | cdc42-dependant
47
What are high density focal adhesions?
RhoA | Actin-myosin interaction-dependant
48
What are 3 signals that are used for motility?
1) Soluble/diffusible 2) Insoluble 3) Fibronectin
49
What are the soluble signals used for motility and how are they used?
Netrins Released from an attraction point and diffuse away to attract cells to that point
50
What are the insoluble signals used for motility and how are they used?
- CAMs and components of the ECM - Inserted into a tissue or the ECM and don't diffuse away - Act as contact attractants
51
Where is fibronectin secreted from? What is this secreted fibronetin used for?
Secreted by migratory cells To lay down a trail which is followed by other migratory cells
52
What 2 things inhibit fibronectin dependant migration?
1) Antibodies binding to fibronectin | 2) RGD motif injection into migratory cels
53
What is the RGD motif and why does injecting it into migratory cells block fibronectin dependant migration?
Arginine - Glycine - Asparagine It is important for fibronectin dependant migration - if artificially administered, it 'swamps' the binding site
54
What are 5 roles of endocytosis in motility?
1) Shaping chemotactic gradients 2) Membrane cycling 3) Confining signalling 4) Modulation of adhesive contact and ECM 5) Polarisation of endocytosis
55
What happens to the membrane of the cell when it is migrating?
- More membrane made to accommodate movement | - Membrane endocytosis around the cell and deposition (exocytosis) at the leading edge
56
What must happen to the membrane for the cell to move forwards?
It must be fixed by focal contacts to the ECM
57
What do integrins facilitate? How?
Cell to extracellular matrix binding Bind to components of the ECM, such as laminin and fibronectin Bind to actin

BMS 242 - Advanced Cell and Molecular (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions