Microfilaments
Microtubules
Microfilaments
Text and image sources are included using the notes function of this file
Microfilament
(thin filament)
structure
minus
G-actin
monomer
ATP
--- 7-8nm
QuickTime™ and a TIFF (Un compres sed ) d ecomp re sso r a re n ee de d to se e this picture.
25nm
plus
G-actin (42-43kD; 375 aas)
(minus)
Animation
(plus)
Changes upon hydrolysis
Intrafilament contacts
QuickTime™ and a TIF F (Uncompressed) decompressor are needed to see this picture.
Polarity of
assembly
(in vitro
assay)
Video
QuickTime™ and a
Video decompressor
are needed to see this picture.
+ G-actin, ATP
Red arrow = minus end
Green arrow = initial plus end
Bulls-eye = contact point on surface
+
-
+
S1
Decoration
-
S1 decoration
reveals
microfilament
polarities in
situ
a. Cytoplasm (mixed polarities)
b. Stress fibers (bundled mixed polarities)
c. Lamellipodia (uniform polarity, points in)
The Angel
of Death
Mushroom
Amanita phalloides
Phalloidin
Cells labeled with
Phalloidin (F-actin)
and
DNase I (G-actin)
Actin
Binding
Proteins
(ABPs)
modulate
architectures
“. . . the actin cytoskeleton is a
complex three-dimensional molecular
jigsaw puzzle” - Tom Pollard
Profilin is involved in ATP recharge
Quic kTime™ and a TIFF (Uncompressed) decom pressor are needed to see this pictur e.
profilin
Cofilin weakens
subunit interactions
by structural
introgression
QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.
Alpha-actinin
crosslinks
microfilaments
Actin subunit
Gelsolin (partial structure)
in presence of Ca++
Amoeboid
motility
uses
Gelsolin
Video
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
F-actin
motilities
Composite time
lapse segments
QuickTime™ and a
Video decompressor
are needed to see this picture.
Actin dynamics
at the leading
edge
GFP::actin in a
tissue culture cell
Qui ckTime™ and a YUV420 codec decompressor are needed t o see t his pict ure.
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
2 time-lapse video sequences
Axonal growth cones
Video
QuickTime™ and a YUV420 codec decompr essor are needed to see this pictur e.
GFP-actin dynamics
Video
Microtubules are excluded
from the periphery
QuickTime™ and a
Animation decompressor
are needed to see this picture.
Cell microinjected with
fluorescent tubulin to
label microtubules
Treadmilling within the lamellipodium
QuickTime™ and a
Video decompressor
are needed to see this picture.
Video
Keratocyte motility
Video
QuickTime™ and a
Sorenson Video decompressor
are needed to see this picture.
Arp2/3 immunolocalization
Quic kTime™ and a TIFF ( Uncompressed) decom pressor are needed to see this pictur e.
Branching out on the
family tree:
the Arp2/3 complex
Coronin
Nucleation Promoting
Factors (NPFs)
WASp/SCAR/Wave
70o
minus
QuickTime™ and a TIFF ( Uncompr essed) decompressor are needed to see this pictur e.
plus
The Actin Family Tree
+
Formin those
long filaments
G-actin monomer
Assembly Cycles
WASp
SCAR
ATP
translation
Formin
CCT
PIP2
WASp
VASp
Arp2/3
Dynamic
F- actinADP
microfilament
G-actinATP
ADP
(exchange)
ATP
Profilin
Stabilizing
ABPs
Thymosin
G-actinADP
VASp
Severin
Gelsolin
Stable
F-actin
microfilament
F-actin
And
VASp
NPF: VASp
(vasodilator stimulated
phosphoprotein)
QuickTime™ and a
Video decompressor
are needed to see this picture.
Video
Signal transduction links
G-proteins
Cdc42
WASp
Arp2/3
WASp*P
PIP
Rac
Rho
PIPkinase
Localized
Initiation
Lamellipodia
Frontal Initiation
PIP2
MLCK
Filipodia
Increased
Turnover
Myosin
Stress fibers
Form and Tension
Formin
Stress fibers
distribute forces
Quic kTime™ and a TIFF ( Uncompressed) decom pressor are needed to see this pictur e.
Arrows highlight
microtubules adjacent
to the stress fiber
bundle
Getting in shape
Neutrophil motility
Video
Microvilli
Anchored in the
terminal web
QuickTime™ and a TIF F (Uncompressed) decompressor are needed to see this picture.
Qui ckTime™ and a TIFF (Uncompres sed) decompres sor are needed to see thi s pic ture.
MyoVIIa is
involved in
Ca++
regulated
adaptation
Qu ickT im e™ an d a T IFF (Un c om pr es se d) de co m pre ss o r a re ne ed ed to s ee th is pic tu re .
Qu ickTi me™ an d a GIF decompre ssor are neede d to see this pi cture.
Stereocilia
Act’in Up
Video
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
Listeria monocytogenes moving in PtK2 cells