the cytoskeleton miklós nyitrai department of biophysics, university of pécs, pécs, hungary. embo...
TRANSCRIPT
![Page 1: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/1.jpg)
The cytoskeleton
Miklós NyitraiDepartment of Biophysics, University of
Pécs, Pécs, Hungary.EMBO Ph.D. course
Heidelberg, Germany
September, 2005
![Page 2: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/2.jpg)
1. What is the cytoskeleton?
2. Filament types and the process of polymerization
3. Motor proteins
![Page 3: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/3.jpg)
So, what is the cytoskeleton?
![Page 4: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/4.jpg)
Cytoskeleton A dynamic structural and functional framework
Three types of filaments:A. IntermediateB. MicrotubulesC. Microfilaments
Cellular distribution of intermediate filaments and microtubules is similar
![Page 5: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/5.jpg)
Polimerization: an exampleThree phases: 1. Lag phase: nucleation 2. Elongation 3. Equilibrium
![Page 6: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/6.jpg)
Equilibrium
1. Dynamic equilibrium
2. Dynamic unstability: slow elongation followed by rapid (catastrophic) depolymerisation
3. ‘Tread-milling’
![Page 7: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/7.jpg)
- Intrinsic flexibility-Thermal (entropy) flexibility (persistence length)
A = persistence length
F
Z = end-to-end distance
Lc = contour length
Polymer mechanics
Bending stiffness:
F
Longitudinal stiffness:F
Torsion:F
Mechanism:
The direction of force:
![Page 8: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/8.jpg)
Microfilaments (actin)
![Page 9: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/9.jpg)
Functions of Microfilaments
Actin filaments are concentrated beneath the plasma membrane (cell cortex) and give the cell mechanical strength.
Assembly of actin filaments can determine cell shape and cause cell movement.
Association of actin filaments with myosin can form contractile structures.
![Page 10: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/10.jpg)
How is a filament built up?
![Page 11: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/11.jpg)
Globular (G-) actin MW: 43 kDa, 375 aa, 1 bound ATP or ADPSubdomains (4)
Actin monomer
![Page 12: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/12.jpg)
The filament
The polymerization...
~100 times faster in vivo than in vitro.
![Page 13: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/13.jpg)
The actin filament (F-actin)
37 nm
~7 nm thick, length in vitro is more than 10 µm, in vivo 1-2 µm
Double helix
Semi-flexible polymer chain (persistence length: ~10 µm)
"barbed end“ and "pointed end" (“barbed” =+ rapid polymerization, “pointed” =- slow polymerization)
![Page 14: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/14.jpg)
Geometry of the Actin Filament
5,5 nm166o
![Page 15: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/15.jpg)
Barbed end Pointed end
Again, a dynamic equilibrium exits and plays central role
Critical concentration
![Page 16: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/16.jpg)
Migrating melanocyte expressing GFP-tagged actin.(Vic. SMALL).
Cell Crawling
![Page 17: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/17.jpg)
What kind of molecular motions are responsible for cell locomotion?
![Page 18: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/18.jpg)
Movement
Subcellular, cellular levels Requires ATP (energy conservation) Cytoskeleton-mediated
Assembly and disassembly of cytoskeletal fibers (microfilaments and microtubules)
Motor proteins use cytoskeletal fibers (microfilaments and microtubules) as tracks
![Page 19: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/19.jpg)
Push and pull!
![Page 20: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/20.jpg)
Cell functions for actinCell functions for actin
![Page 21: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/21.jpg)
Microtubules
![Page 22: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/22.jpg)
Subunit: tubulinMW: ~50 kD, - és -tubulin -> heterodimer1 bound GTP or GDP;
Microtubules
![Page 23: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/23.jpg)
Microtubules
~25nm thick, tube shape13 protofilaments Right hand, short helixLeft hand, long helixStiff polymer chain (persistence length: a few mm!)Structural polarization:
+ end: rapid polymerization, - end: slow polymerization
GTP-cap see ‘search and capture’
![Page 24: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/24.jpg)
Intermediate filaments
![Page 25: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/25.jpg)
The monomer is not globular, a fiber!
Tissue specific IF types
Nuclear lamins A, B, C lamins
(65-75kDa)
Vimentin type Vimentin (54kDa)
Desmin (53kDa)
Peripherin (66kDa)
Keratins Type I (acidic) (40-70kDa)
Type II (neutral/basic) (40-70kDa)
Neuronal IF neurofilament proteins (60-130kDa)
![Page 26: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/26.jpg)
The subunit of filaments: „coiled-coil” dimerVimentin dimer
![Page 27: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/27.jpg)
Polymerisation of IF
protofilamentum
filamentum
Polymerised in celllack of dynamic equilibrium
Central rods (-helix) hydrofob-hydrofob interactions -> colied-coil dimer
2 dimer -> tetramer (antiparallel structure)
Tetramers connected longitudinally -> protofilaments
8 protofilaments -> filament
![Page 28: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/28.jpg)
Cytoskeleton associated proteins
Many families of proteins which can bind specifically to actin
A. According to filaments1. Actin-associated (e.g. myosin)2. MT- associated (e.g. Tau protein)3. IF- associated
B. According to the binding site1. End binding proteins (nucleation, capping, pl. Arp2/3, gelsolin)2. Side binding proteins (pl. tropomyosin)
C. According to function 1. Cross-linkers
a. Gel formation (pl. filamin, spectrin)b. Bundling (pl. alpha-aktinin, fimbrin, villin)
2. Polymerization effectsa. Induce depolymerization („severing”, pl. gelsolin)b. Stabilizing (pl. profilin, tropomiozin)
3. Motor proteins
![Page 29: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/29.jpg)
Actin nucleation factors
What are they for?
![Page 30: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/30.jpg)
The atomic model of Arp2/3The atomic model of Arp2/3(Andrea Alfieri)(Andrea Alfieri)
inactive stateinactive stateArp2
p34
p16p16
p20
Robinson et al., 2001. Crystal structure of Arp2/3 complex. Science. 294:1679-84.
p40
p21Arp3
![Page 31: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/31.jpg)
The Arp2/3; active stateThe Arp2/3; active state
Volkmann, et al., 2001.Structure of Arp2/3 complex in its activated state and in actin filament branch junctions.
Science. 293:2456-9.
![Page 32: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/32.jpg)
The cytoskeleton can be hijacked based on the use of Arp2/3!
![Page 33: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/33.jpg)
Intracellular pathogens
![Page 34: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/34.jpg)
Polystyrene beads of different diameters (0.5, 1, 3µm) have been functionalized with N-WASP and placed in a reconstitued motility medium containing actin, Arp2/3 complex, ADF/Cofilin, gelsolin (or any capping protein) and profilin.
In vitro model
![Page 35: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/35.jpg)
Formins(Manuelle Quinoud)
A proposed mechanism from S. Zigmond.
![Page 36: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/36.jpg)
Motor proteins(why ‘motor’?)
![Page 37: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/37.jpg)
1. They can bind to specific filament types
2. They can travel along filaments
3. They hydrolyze ATP
Motor proteins
![Page 38: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/38.jpg)
1. Actin-based: myosinsConventional (miozin II) and nonconventional
myosinsMyosin families: myosin I-XVIII
2. Microtubule based motorsa. Dynein
Flagellar and cytoplasmic dyneins. MW~500kDaThey move towards the minus end of MT
b. Kinesin Cytoskeletal kinesins Neurons, cargo transport along the axons Kinesin family: conventional kinesins + isoforms. MW~110 kDa They move towards the minus end of MT
3. Nucleic acid basedDNA and RNA polymerasesThey move along a DNA and produce force
Types of motor proteins
![Page 39: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/39.jpg)
Motor proteins
“Walk” or slide along cytoskeletal fibers Myosin on microfilaments Kinesin and dynein on microtubules
Use energy from ATP hydrolysis Cytoskeletal fibers:
Serve as tracks to carry organelles or vesicles
Slide past each other
![Page 40: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/40.jpg)
1. StructureN-terminal globular head:
motor domain, nucleotide binding and hydrolysis specific binding sites for the corresponding filaments
C-terminal: structural and functional role (e.g. myosins)
2. Mechanical properties, functionIn principle: cyclic function and workMotor -> binding to a filament -> force -> dissociation -> relaxation1 cycle requires 1 ATP hydrolysis
They can either move (isotonic conditions) or produce force (isometric conditions)
Common properties
N
C
![Page 41: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/41.jpg)
The ATP hydrolysis cycle: an example
![Page 42: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/42.jpg)
€
r =τon
τon+τoff
=τon
τtotal
The working cycle of motor proteins
€
v=δτon
€
τtotal=1V
€
τon=δv
Duty ratio:In vitro sliding
velocity:Cycle time:Attached time:
attachedon
detachedoff
ATP cyclepower stroke
back stroke
attachment detachment
= working distance
=working distance (or step size); V=ATPase activity; v=In vitro sliding velocity
![Page 43: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/43.jpg)
€
r =δVv
Processivity and the duty ratio
Processive motor: r->1pl. kinesin, DNA-, RNA-polimerasethe motor is attached to the track in most of the working cycle
Nonprocessive motor: r->0pl. conventional myosin
A motor protein can produce force in the pN range.
=working distance or step sizeV=ATPase activityv=in vitro motility velocity
![Page 44: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/44.jpg)
Myosins
![Page 45: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/45.jpg)
The superfamily
![Page 46: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/46.jpg)
Diversity, adaptation, tuning
![Page 47: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/47.jpg)
How do myosins work?
![Page 48: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/48.jpg)
An example: the myosin in muscle cells
![Page 49: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/49.jpg)
The head group of the myosin walks toward the plus end of the actin filament.
Cell functions for myosinsCell functions for myosins
![Page 50: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/50.jpg)
Kinesins
![Page 51: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/51.jpg)
Kinesin scheme
Single headed kinesins!?
![Page 52: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/52.jpg)
Walking along the microtubules
Also remember processivity…
![Page 53: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/53.jpg)
So, how does it all work together?
![Page 54: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/54.jpg)
Pollard and Beltzner, Current Opinion in Structural Biology 2002, 12:768–774.
An example for actin cytoskeleton regulation
![Page 55: The cytoskeleton Miklós Nyitrai Department of Biophysics, University of Pécs, Pécs, Hungary. EMBO Ph.D. course Heidelberg, Germany September, 2005](https://reader033.vdocuments.us/reader033/viewer/2022052414/56649c6d5503460f9491f7d5/html5/thumbnails/55.jpg)
Thank You!