Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
20 Cards in this Set
- Front
- Back
|
Actin filaments are different
|
depends on the cell type.
|
|
|
actin polymerizations is
|
described by rate constants
|
|
|
Net growth
|
Subunites added - Subunits lost
= Kon (subunits) - Koff |
|
|
Cc( critical values)
|
subunits when net growth is zero = Koff/Kon
|
|
|
Actin regulators allow cells to build diverse and dynamic actin networks
|
Grow the filament: Formins
Actin is a very fast polymerizing. Formins can act either as a catalyst to speed up or a gatekeepers to slow thang down |
|
|
Cut the fillament
|
ADF/Cofillin by fragmenting and increasing ends that being depolmerize
|
|
|
Cap the filament
|
Capping Protein.
|
|
|
Make branched network
|
Arp2/3
|
|
|
cross-linkers have 2 opposing filament binding domains
|
fimbrim : 2 actin binding domain
alpha-actinin: only one binding domain but can heterodize with itself. Spectrin: cell cortex |
|
|
The leading edge if a moving cells is a branched actin network
|
cell constructing network.
tread mill space |
|
|
A pathogenic bacterium hijacks the actin machinery of human cells
|
Listeria monocytogenes: hijacks the actin to drive them results in cosmic tails
|
|
|
Arp 2/3 mimics an
|
actin nucleus and nucleates daughter filaments at 70 degree
|
|
|
Push out plasma membrane
|
at 70 percent.
|
|
|
The lamellipodium must overcome 2 majors challenge
|
1. run out of actin
2. Preventing futile polyerization. |
|
|
!. Run out of actin
|
Recycles actin and block s minus end polymerization with profilin by crack open the actin and kickout ADP and lead ATP in.
When profilin bind to actin thus prevent by blocking the smooth end of the actin. |
|
|
ADF/Cofilin severs actin filaments
|
untwist actin filament and make it supceptible to breakeafe. Cofilin only likes to bind to polymeric actin. to
|
|
|
Need bot cofilin and profilin
|
and some Thymosin-B4 keeps actin in reserve to sequest the actin)
|
|
|
Capping proteins
|
prevent futile polymerization.
1.5 seconds to find an open ends. |
|
|
Listeria harness this machinery by
|
activating the Arp 2/3 and which mean that the movement of Listeria can be reconstituted from purified components.
highly possesive |
|
|
Formins
|
polymerize linear actin filaments arrays.
FH2 = formins homology. polyerase. FH1 doamin binds |
