Lamellipodial extension driven by actin assembly
Download
1 / 24

Lamellipodial extension driven by actin assembly - PowerPoint PPT Presentation


  • 100 Views
  • Uploaded on

Lamellipodial extension driven by actin assembly. Rac-GTPase. lamellipodia. lamella. Svitkina T.M. and Borisy G.G., 1999, J Cell Biol, 145:1009-26. Pollard T.D. and Borisy G.G., 2003, Cell, 112:453-65. actin plolymerization (front) and depolymarization (rear)

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Lamellipodial extension driven by actin assembly' - bianca-clark


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Lamellipodial extension driven by actin assembly

Rac-GTPase

lamellipodia

lamella

Svitkina T.M. and Borisy G.G.,

1999, J Cell Biol, 145:1009-26

Pollard T.D. and Borisy G.G., 2003, Cell, 112:453-65

actin plolymerization (front) and

depolymarization (rear)

define the lamellipodial width

Forces generated by Myosins?

Cell spreading and migration require myosin activity


Release

Extension

Contraction

Attachment

Recycling

x

t

e

i

o

C

o

n

t

r

a

c

t

i

o

n

F

o

r

c

e

F

o

r

c

e

R

e

l

e

a

s

e

R

e

c

y

c

l

i

n

g


Cell migration: a cyclic process of force generation

1. lamellipodial extension:

forward force exerted by actin polymerization

on the membrane

2. extracellular matrix probing:

rearward force exerted by actin flow

on integrins

How the cell locally transduces

the rigidity of the ECM

into a contractile signal

used to direct lamellipodial extension?

Sheetz M.P., Felsenfeld D.P., Galbraith C.G., 1998, Trends Cell Biol, 8:51-4


Neural crest migration
Neural Crest Migration

  • The peripheral nervous system is created by a spatiotemporally co-ordinated migratory process during which the precursor cells, the neural crest (NC) cells, traverse the embryo to reach distantly located sites.


  • Homing of peripheral neurons and their supportive cells might be dictated by a delicate equilibrium between the multiple actions of stimulatory and inhibitory molecules, which is modulated further by defined responses of the dispersing cells to these ECM components during their successive phases of phenotypic diversification.


Extracellular matrix integrin interactions in motility and signaling
Extracellular Matrix-Integrin Interactions in Motility and Signaling

Matrix molecules are typically bound by integrins

Integrins are alpha-beta dimeric membrane proteins needed for motility, signal, and force transduction.

Antibodies to integrins block cell migration and spreading




Steps in nc migration
Steps In NC Migration Signaling

  • Initiation of migration

  • Migration

  • Homing

  • Differentiation



Initiation of migration
Initiation of Migration Signaling

  • Transition from tissue ball to migration

  • Loss of cadherins

  • Acquisition of Integrins

  • Acquisition of motile machinery

  • Stimulus to migrate


Important Aspects of Migration Signaling

1. Isovolumic

2. Constant Membrane Area

3. Actin filament assembly and disassembly

4. Actin filament contraction

5. Matrix binding

6. Matrix Rigidity

7. Release of matrix binding



Matrix Forces Directed Signaling

Inward And Balanced

time

4

c

e

l

l

d

i

r

e

c

t

i

o

n

rear

3

)

2

m

2

n

u

c

l

e

u

s

m

/

1

N

f

r

o

n

t

n

(

0

n

o

i

t

c

-

1

a

r

T

-

2

-

3

-

4


How does a cell treat the ecm
How does a cell treat the ECM? Signaling

  • Movie 2: One cell deforms a collagen fibre


Release Signaling

Extension

Contraction

Attachment

Recycling

x

t

e

i

o

C

o

n

t

r

a

c

t

i

o

n

F

o

r

c

e

F

o

r

c

e

R

e

l

e

a

s

e

R

e

c

y

c

l

i

n

g


ad