Cytoskeleton 1

Question 1

What is the cytoskeleton?

Answer 1

Scaffold and structure framework responsible for cell movement.
-actin, intermediate filaments, and microtubules

Question 2

G actin

Answer 2

Monomers with binding sites for other G actin. Dimer and trimer formation called nucleation.

Question 3

F actin

Answer 3

Monomers of g actin added together in elongation step.

Question 4

Monomers add to

Answer 4

Barbed (+) end.

Requires ATP

Question 5

Monomers removed from

Answer 5

Pointed (-) end

Requires Pi release

Question 6

Steady state

Answer 6

Rate of assembly = rate of disassembly

Question 7

Treadmilling

Answer 7

Addition and subtraction at same time leaving filament length unchanged

Question 8

Formin

Answer 8

Binds to actin monomers, facilitating nucleation by adding monomers until it’s released.

Question 9

Arp2/3

Answer 9

Binds near barbed end and initiates branch formation, stays bound.

Question 10

ADF/cofilin

Answer 10

Binds to ADP actin at pointed end, enhancing dissociation rate and prevents filament binding.

Question 11

Profilin

Answer 11

Increases exchange of ADP for ATP on G actin monomers, stimulating filament formation

Question 12

CapZ

Answer 12

Binds to + end inhibiting polymerizatiom

Question 13

Troomodulin

Answer 13

Binds to - end preventing dissociation of actin

Question 14

Fimbrin

Answer 14

Holds two actin filaments in parallel using Ca2+ to aid. Supports plasma membrane

Question 15

a-actinin

Answer 15

Holds 2 filaments together so they can contract, held further apart
Spacer domain

Question 16

Filamin

Answer 16

Cross links actin in NETWORK. Supports cell surface

Question 17

Cell migration

Answer 17

Filopodia (filaments) go first followed by lamellopodia (actin bundles)

Question 18

WASP/Scar complex

Answer 18

Activated Arp2/3

Question 19

Barbed end tracking proteins

Answer 19

Connect growing actin filaments to plasma membrane

Question 20

Wiskott Aldrich Syndrome

Answer 20

Inherited immunodeficiency disease, white blood cells disrupted and bleed easily due to mutation in WASP protein (doesn’t activate Arp2/3 for branching)

Question 21

Twinfilin

Answer 21

Carries to barbed end