Exam 4 (9)

Question 1

Lamellipodia Actin: what’s happening there?

Answer 1

Plus end growth leads to a slight force with a lot of pushback to the rigidity of the membrane; this is simultaneously paired with cofilin (-) end depolymerization –> Actin is said to be undergoing retrograde flow!!
Therefore, the cell only makes slight forward movements

Question 2

How do cells “gain traction”/make the movement effort more worth it?

Answer 2

A connection is created between the focal adhesions, integrins, and actin network to create a clutch/anchor
Slows down retrograde flow and causes more protrusion!!

Integrins move toward leading edge as movement occurs to be ready for the next anchorage

Question 3

True Motion of Cells

Answer 3

Rather oscillatory; Goes extensively out and is severely retracted and grabs most forward focal adhesion (formation of an actin arc) –> edge of cell retracts
Net movement is forward, unless focal adhesion slips backwards

Question 4

Intracellular Transport in Neurons

Answer 4

The Axon!!

Kinesins (+) to go towards terminal
Dyneins (-) to go to soma/cell body