ACTIN
·
CYTOSKELETON : 4 POLYMER SYSTEMS · CRITICAL CONC
mitosis & cytokines is
- -
DATP activ monomer
② ATP-
> ADD + Pi
③ P ; released > App actin =
actin conc
<0
. . 1MM => F-act
0 6 MM
.
=>
a
grows
conc -
bin 0 12 MM & 0 6 MM =
.
.
g
·
TREADMILLING /Steady state assem
- a monomer conc .
3/1 Cc o
↳ rate of growth& end-
=> constant filament leng
=> monomes more through
o
ACTIN ↳ Steady state : active tread
↳ monomer: G-actin , polymer : F-actin (filaments ↳ Aip present , activ polymeriz
polymerization initiated G-activ (Mg2+, k) treadmilling a steady
+
↳ activ Solution w/ salt & s
① of light :
menoring scattering nemy adde
solution & monomers soluble in vitro length unchanged ,
- pommer scatter more light , dense in
-
② purene-activ & Spectrophotometry activ filament
attach finorescent 0000000
321x0ac
-
tag (Purene) to actin ↓
O t
F-actin fluorescence more
-
-
brightly
③
visualizing filaments by fluorescence/e-microscopy pooddoxo
O
F-actin larger, Sediment more readily by centrifugation
oxoddoxo
-
·
ACTIN ASSEMBLY
↳ polymerization rate
e barbed end X10 faster than pointed & end
Onudeation : formation of 3 activ monomers (nucleus) ·
ACTIN BINDING PROTEIN (ABPS)
lay phase unstable activ dimen ↳ regulate polymerization
-
,
eliminated by factors (F-actin ↳ Thymosin B4 (depolymeriza
lay can be
adding nucreating
-
20
elongation : subunit add onto nuclei ->
growth ,
fast -
bind ATP monomer & p
③ steady state : ↳ Prolifin
=
(polymerization)
-
-
no net ↑/d in amount of polymerized activ -
binds & end App G-acti
-
rate of G-actin addition rate of G-activ falling off from
=
each other -
actin polymerization onto
-
CONC of free active Steady state critical conc (Col = .
-
can't uncreate to form
Cc f
=
=> control growth
Kor
conc .
monomer < Cc => depolymerization ↳ Cofilin (polymerization/depoly
(on rate s off rate, -
interact ul App activ mo
conc ·
monomer > C =
Polymerization
-
fragment has && end
, /ABP)
ACTIN BINDING PROTEIN
·
DRUGS THAT AFFECT POLYMERIZATION ·
ABP :
CROSSLINKING PROTEIN
↳ long spacer : get like netwo
↳ short spacer : short bundle
↳ membrane-actin linker p
·
ABP
>
- stabilize filament by binding to ends, prevent addition/loss
> bind along length of filament , polymerization
-
[ cofilin :↑ depolymerization rate create & ends
disassemble ] ,
ACTIN-BASED MOTOR
gesolin : sever activ filament
o
MYOSIN
activated
↳ energy from ATP hydrolysis
GTPases >
-
WASP > Arp2/s
protein - O Myosin 1 :
single head , mo
Myotin 11 dimer (2 heads ,
3 Myosin
:
v : walk & re
>
- carry
·
ABD : control polymerization & depolymerization -
at least I head always
a remain associated & end
forming : nudeate new F-actin formation Myosin VI only myosin m
·
:
=
=
thymogin B4 :
Sequester lisolates monomer prevent polymerization
-
,
Arp2/3 :
⑤
interact sides of filament & branch new filament, Polymerization · ACTIN FILAMENT SLIDING ASSAY
profilin : binds
=
monomer Alp bound , olymerization ↳ actin bind to 1 myosin => fila
& cofilin i
↳ = 2
myosin
=
st
5 gelcolin :
severing proteins , depolymerization
·
CYTOSKELETON : 4 POLYMER SYSTEMS · CRITICAL CONC
mitosis & cytokines is
- -
DATP activ monomer
② ATP-
> ADD + Pi
③ P ; released > App actin =
actin conc
<0
. . 1MM => F-act
0 6 MM
.
=>
a
grows
conc -
bin 0 12 MM & 0 6 MM =
.
.
g
·
TREADMILLING /Steady state assem
- a monomer conc .
3/1 Cc o
↳ rate of growth& end-
=> constant filament leng
=> monomes more through
o
ACTIN ↳ Steady state : active tread
↳ monomer: G-actin , polymer : F-actin (filaments ↳ Aip present , activ polymeriz
polymerization initiated G-activ (Mg2+, k) treadmilling a steady
+
↳ activ Solution w/ salt & s
① of light :
menoring scattering nemy adde
solution & monomers soluble in vitro length unchanged ,
- pommer scatter more light , dense in
-
② purene-activ & Spectrophotometry activ filament
attach finorescent 0000000
321x0ac
-
tag (Purene) to actin ↓
O t
F-actin fluorescence more
-
-
brightly
③
visualizing filaments by fluorescence/e-microscopy pooddoxo
O
F-actin larger, Sediment more readily by centrifugation
oxoddoxo
-
·
ACTIN ASSEMBLY
↳ polymerization rate
e barbed end X10 faster than pointed & end
Onudeation : formation of 3 activ monomers (nucleus) ·
ACTIN BINDING PROTEIN (ABPS)
lay phase unstable activ dimen ↳ regulate polymerization
-
,
eliminated by factors (F-actin ↳ Thymosin B4 (depolymeriza
lay can be
adding nucreating
-
20
elongation : subunit add onto nuclei ->
growth ,
fast -
bind ATP monomer & p
③ steady state : ↳ Prolifin
=
(polymerization)
-
-
no net ↑/d in amount of polymerized activ -
binds & end App G-acti
-
rate of G-actin addition rate of G-activ falling off from
=
each other -
actin polymerization onto
-
CONC of free active Steady state critical conc (Col = .
-
can't uncreate to form
Cc f
=
=> control growth
Kor
conc .
monomer < Cc => depolymerization ↳ Cofilin (polymerization/depoly
(on rate s off rate, -
interact ul App activ mo
conc ·
monomer > C =
Polymerization
-
fragment has && end
, /ABP)
ACTIN BINDING PROTEIN
·
DRUGS THAT AFFECT POLYMERIZATION ·
ABP :
CROSSLINKING PROTEIN
↳ long spacer : get like netwo
↳ short spacer : short bundle
↳ membrane-actin linker p
·
ABP
>
- stabilize filament by binding to ends, prevent addition/loss
> bind along length of filament , polymerization
-
[ cofilin :↑ depolymerization rate create & ends
disassemble ] ,
ACTIN-BASED MOTOR
gesolin : sever activ filament
o
MYOSIN
activated
↳ energy from ATP hydrolysis
GTPases >
-
WASP > Arp2/s
protein - O Myosin 1 :
single head , mo
Myotin 11 dimer (2 heads ,
3 Myosin
:
v : walk & re
>
- carry
·
ABD : control polymerization & depolymerization -
at least I head always
a remain associated & end
forming : nudeate new F-actin formation Myosin VI only myosin m
·
:
=
=
thymogin B4 :
Sequester lisolates monomer prevent polymerization
-
,
Arp2/3 :
⑤
interact sides of filament & branch new filament, Polymerization · ACTIN FILAMENT SLIDING ASSAY
profilin : binds
=
monomer Alp bound , olymerization ↳ actin bind to 1 myosin => fila
& cofilin i
↳ = 2
myosin
=
st
5 gelcolin :
severing proteins , depolymerization
