Motors, Actin, Cell Motility (Motility)

Question 1

Profilin

Answer 1

Actin - binding protein that enhances the growth of filaments

Question 2

Cofilin

Answer 2

Actin binding protein that disassembles actin filaments

Question 3

Capping protein

Answer 3

Blocks the exchange of subunit at the (+) end

Question 4

Directed cell motility

Answer 4

• Coordinated activity of actin binding proteins controls microfilament formation in a lamellipodium to allow directed cell movement
• A lamellipodium is an actin projection on the leading edge of a cell

Question 5

Myosins

Answer 5

• A super family of motor proteins associate with microfilaments

-The large number of membranes in the myosin superfamily is illustrated in the panel below

Question 6

Conventional myosin

Answer 6

• Type II
• Primary motors for muscle contraction

Question 7

Unconventional myosins

Answer 7

• Type I and types III-XVIII

-Generate force and contribute to motility in non-muscle cells

• Actin-based protrusion of leading edge (lamellipodium) powered by actin growth
• Myosin-based contraction pulls
  trailing edge forward

Question 8

Microtubule based and microfilament based motors

Answer 8

-Can cooperate in intracellular transport