Lecture 7: Cytoskeleton

Question 1

Microfilaments

Answer 1

Component of cytoskeleton which constitute actin and bind to transmembrane proteins (7 nm thick)

Question 2

Treadmilling

Answer 2

Dynamic equilibrium between minus and plus end of microfilaments, favored by intermediate concentration. Maintains the length.

Question 3

Cytochalasins

Answer 3

Drug that binds to barbed ends of microfilaments, blocks elongation and can inhibit movement. Cytochalasins stop telophase from happening so cell division does not occur

Question 4

Gelsolin

Answer 4

Destabilizes F-actin and caps actin filaments, preventing loss and addition of G-actin

Question 5

Thymosin

Answer 5

controls treadmilling by capturing actin monomers and preventing polymerization

Question 6

Profilin

Answer 6

Binds to actin monomers and prevents monomers from being polymerized-exchange of bound ADP for ATP which favors polymerization (controls treadmilling)

Question 7

Cofilin

Answer 7

Controls treadmilling by triggering depolymerization of ADP bound actin at the minus end

Question 8

Arp2/3

Answer 8

Controls treadmilling; Initiates growth of F-actin from sides of existing filament, cause branching

Question 9

Latrunculins

Answer 9

Controls treadmilling; Bind to G-actin and induces F-actin depolymerization

Question 10

Intermediate filaments

Answer 10

abundant in cells that undergo mechanical stress, provide tensile strength, scaffolding for cell

Question 11

Microtubules

Answer 11

polarized filaments that undergo dynamic instability, many functions

Question 12

Colchicines

Answer 12

Drug that binds to the tubulin dimers of microtubules and prevent polymerization

Question 13

Taxol

Answer 13

Drug that binds to microtubules preventing their depolymerization (stabilizes microtubules).

Question 14

Cytoskeletal functions

Answer 14

Cell movement, support/strength, phagocytosis, mitotic spindle formation, cytokinesis, cell/cell and cell/ECM adherence, changes in cell shape