Lecture 5: Cytoskeleton II

Question 1

What does cell migration depend on?

Answer 1

-Enhanced actin nucleation at the leading edge of the cell
-dynamic attachment of the cells to the substratum
-myosin dependent contraction at the trailing edge

Question 2

External signals lead to the activation of small __ which induce changes in actin organization to promote cell movement

Answer 2

GTPases (Rho, Rac and Cdc42)

Question 3

What is the activity of small GTPases determined by ?

Answer 3

GEF and GAP proteins

Question 4

GEF ___ the small GTPases

Answer 4

activate

Question 5

GAP to ___ the small GTPase

Answer 5

inactivate

Question 6

In skeleton muscle contraction during relaxed state __ and __ are prevented from interacting through specific acting binding proteins

Answer 6

F-actin and myosin

Question 7

During contraction ___ ____ induces the binding between F-actin and myosin

Answer 7

increased Ca2+

Question 8

In smooth muscle contraction:

Answer 8

1. Ca2+ in the cytosol binds calmodulin
2. activates myosin light chain kinase

Question 9

Troponin is found in

Answer 9

skeletal muscle

Question 10

Ca2+ level increase

Answer 10

activates myosin and myosin binds to F-actin

Question 11

Myosins are ___ based motor proteins

Answer 11

actin

Question 12

Tropomyosin occupy the myosin binding site on __ and block __

Answer 12

F-actin, muscle contraction