L19 - Rho,Integrins and extracellular matrix Flashcards
(10 cards)
lammeliopodia vs filopodia simple
lammeliopodia:
branched actin network - Arp2/3 mediated - Rac-WAVE
- cell movement
Filopodia:
parralel and tight actin filaments - Arp2/3 mediated - Cdc42 - N-WASP
describe what stress dibres are and their function
contractile antiparralel actin bundles with mysosin 2
= cell tension and force transmission
what is RhoA
RhoA is a Rho-family GTPase
= regulates assembly of stress dibvres and actomyosin contractility
describve the activation pathwat of RhoA in controlling contractility
- RhoA-GTP activates ROCK (Rho-ascociated kinase)
- active ROCK:
- phosphorylates mysoin light chain –> activates myosin-2 - promotes actomysoin contraction WITHIn stress fibres –> contractile forces
= drag rear of cell during cell migration
how do cells intercat with the ECM
integrins
= connect to focal adhesions and actin cytokeleton
roles of collagen and fibroconnectins in ECM
ECM< prvides structural and mechancical suupport to cells
Collagen -> main structural protein
Fibroconnectin -> cell adhesion + migration scaffold
what doe the term mechanosensitive mean in terms of ECM
cells respond to the ECM ‘Stiffness’ via mechanotransduction
how do: Soft,intermeiate and stiff ECM stiffness influence cell behavior
soft -> rounded cells + slow migration
intermediate -> differetiation favored
Stiff –> flattened morphology + increased stress fibre formation
how does the ECMs stiffness affect cells via RhoA
Stiff matrices activate RhoA –> activate ROCK
= increased myosin-2 activity
= more contractile force
cells use focal adhesions to ‘pull’ on the matrix to assess ridgity
whatv are focal adhesions
large protein complexes that form the PHYSICAL signalling links between the ECM and actin cytoskeleton
= mechanotransduction-> sense + respond to ECM stiffness
- cell attach firmly via integrins
