Cell

Front 1

MTOC(Microtubule organizing center)

Back 1

Accessory protein that stabilizes the - end and aids in nucleation. It forms a centrosome with 2 centrioles that localize to the center of the cell. Forms during cell fragmentation.

Front 2

Stathmin

Back 2

Accessory protein that regulates polymerization in MT. It attaches to heterodimers and does not allow them to form MT, It binds to free tubulin and when they are released they phosphorylate the stathmin

Front 3

MAPS(Microtubule associated proteins)

Back 3

Accessory protein stabilizer. They attach to the sides of filaments to stablized or destabilize. They set the density for the MT, which stablizes them. They are destablized by catastrophe factor/kinesin 13

Front 4

Kinesin 13`

Back 4

Destabilizer of MT

Front 5

Function of the cytoskeleton

Back 5

Keeep cells in shape
-conformation
-contraction
-can combine for movement

Front 6

Function of MT?

Back 6

Organelle positioning and intracellular transport

Front 7

Function of AF?

Back 7

Surface shape and locomotion

Front 8

Function of IF?

Back 8

To provide strength

Front 9

Accessory proteins

Back 9

Link filaments to other parts of the cell and other filaments within the cell. Regulate and localize assembly of filaments

Front 10

Describe the construction of MT

Back 10

alpha and beta heterodimers form strands called protofilaments. 13 of these protofilaments line up to form the MT

Front 11

Describe the construction of AF

Back 11

An actin subunit with an ATP side. Protofilaments which are twisted like DNA

Front 12

Name the 4 keys in the assembly of AFs and MTs

Back 12

1. Noncovalent bonding- allows subunits to break easier
2. Subunits diffuse readily allowing for easier position change
3. Subunits self-associate allowing for easier assembly
4. Subunits are G/ATP-associated enzymes allowing for differences in assembly

Front 13

Explain the growth of AF and MT

Back 13

+ end is faster than the (-) which means the + end has more T's because they dont get turned into D's fast enough. They bind in the T form and dissociate in the D form.

Front 14

Dynamic Instability

Back 14

GTP-bound tubulin attaches to the MT and then hydolysis and turns into GDP and falls off. GDP-bound tubulin in the middle of a MT cannot fall off because the MT contains a GTP-bound tubulin cap, but when hydrolysis catches up to the tip you get rapid dissassembly until another cap is added

Front 15

Where are Intermediate filaments located in the body?

Back 15

In cells that undergo mechanical stress(finger nails)

Front 16

Are all 3(MT, AF, IF) polarized?

Back 16

AF and MT are, but IF are not polarized.

Front 17

Describe the construction of an IF.

Back 17

Take 2 helical monomers and twist them into 2 coiled dimer. Then take 2 coiled dimers and twist them to make a staggered tetramer so that NH2 and COOH are lined up at each end.

Front 18

What are some examples of IFs?

Back 18

Keratin and neurofilaments

Front 19

Actin Related Proteins

Back 19

Accessory proteins that aid in nucleation. They localize at the PM and can attach to existing AF to form a web

Front 20

Formins

Back 20

Circular rings that attach to the + end of Actin and mediate elongation. They form bundles instead of branches

Front 21

Name the 2 proteins that aid in the nucleation of AF

Back 21

Formins and Actin related proteins

Front 22

What is the protein that aids in the nucleation of MT?

Back 22

MTOC

Front 23

Regulating protein in MT

Back 23

Stathmin

Front 24

Regulating protein in AF

Back 24

Thymosin

Front 25

Thymosin

Back 25

Regulating Accessory protein the binds to free actin and does not allow them to create AF. When they are released, they create profilin which speeds up elongation

Front 26

Profilin

Back 26

Created after Thymosin is released from actin subunits, It attaches to these subunits and competes for binding, but has a higher affinity and speeds up elongation.

Front 27

MAPs(MT-associating proteins)

Back 27

They regulate stabilization by binding to the sides of tubules. They also set the density and can destabilize the MT(catastrophe factor)

Front 28

Cofilin

Back 28

Regulating stabilization protein that destabilizes AF by causing tighter twists which make it easier to break. Binds to ADP-actin

Front 29

Protein caps

Back 29

Attach to the + end in AF and slow or stop the growth of actin. Also a regulating stabilization protein

Front 30

Name the two ways to destabilize AF without severing

Back 30

Cofilin and protein caps

Front 31

How is severing different than destabilization?

Back 31

Severing cuts the filament to promote faster degredation and then faster polymerization of new ones

Front 32

Katnin

Back 32

Severing protein that cleaves MT from the centrosome and causes depolymerization and requires ATP

Front 33

Gelsolin

Back 33

Activated by high levels of Ca2+ and cuts the actin filament then attaches to the + end

Front 34

Cross linking

Back 34

organizes filaments into a web and links different filaments into networks

Front 35

Filaggrin

Back 35

Accessory protein that bundles keratin together in the epidermis to give it more strength

Front 36

Plectin

Back 36

Cross liking accessory protein that attaches to IF as well as MT, AF, motor proteins, and the PM

Front 37

How are AFs linked?

Back 37

1. Bundling proteins that like AFs in parallel arrays
2. Gel-forming proteins that hold 2 AFs at large angles

Front 38

Fimbrin/villin

Back 38

cross linking accessory protein that bundles AFs CLOSELY together in parallel arrays

Front 39

alpha-actinin

Back 39

Cross linking accessory protein that bundles AFs FAR APART in parallel arrays

Front 40

Filamin

Back 40

Cross linking accessory protein that links AF into a 3D network with the physical properties of a gel(2 AF)

Front 41

Cross linking

Back 41

organizes filaments into a web and links different filaments into networks

Front 42

Filaggrin

Back 42

Accessory protein that bundles keratin together in the epidermis to give it more strength

Front 43

Plectin

Back 43

Cross liking accessory protein that attaches to IF as well as MT, AF, motor proteins, and the PM

Front 44

How are AFs linked?

Back 44

1. Bundling proteins that like AFs in parallel arrays
2. Gel-forming proteins that hold 2 AFs at large angles

Front 45

Fimbrin/villin

Back 45

cross linking accessory protein that bundles AFs CLOSELY together in parallel arrays

Front 46

alpha-actinin

Back 46

Cross linking accessory protein that bundles AFs FAR APART in parallel arrays

Front 47

Filamin

Back 47

Cross linking accessory protein that links AF into a 3D network with the physical properties of a gel(2 AF)

Front 48

Spectrin

Back 48

Like a bundler but long and flexible and attaches to the PM. This is how AF stay localized at the PM`