Cell migration Flashcards
4 steps of cell migration
polarity, protrusion, traslocation, retraction
Arp2/3 complex
heptomer which sits on a pre existing actin filament at 70 degrees to form a branch
capping proteins in Actin
β-actinin, CapZ or Cap32/34
- help favor actin assembly by preventing the loss of actin subunits to the barbed end
- stability, direction and short dense network
Ena/VASP
protein family accumulates at the plasma membrane to antagonize barbed end capping proteins and to enable actin polymerization into longer filaments
possibly could be used in filopodia? or stress fibres
ADF/cofilin
chops up actin behind the leading edge into G actin monomers - recycled into new filaments
profilin
catalyses the regeneration of ATP actin from ADP
Cdc42- branched actin
cdc42 activates WASP which activates Arp2/3
thymosin
antipolymerisation - sequesters actin monomers
thymosin and profiling compete
to find actin monomers
how to listeria hijack the cell
they have the protein ActA which is similar to mammalian WASP - recruits the Arp2/3 complex and so uses actin to move around the cell
why would ActA not be a good target on its own for treating listeria
because it is unlikely that it is the only protein which is involved in invading cells - and also high rate of mutation. Also difficult to target when it is the same as our WASP
what is blebbing
when cells move by pushing their membranes forwards - don’t make adhesions - driven by actin polymerisation
ahesions
focal adhesions made using intergrins
filopodia
migrating growth cones + fibroblasts
long thin bundles of actin
Lameolopodia -
epithelial cells and fibroblasts and some neurones
contain all the machinery for cell motility
well studied in epithelial cells of epidermis in fish and frogs - been shown to close wounds at 30um/min
