Consider an actin subunit that has just been incorporated into an actin filament at the leading edge of a lamellipodium. Before its ATP is hydrolyzed, how does its distance from the leading front edge of the plasma membrane change over time? How does its distance from the F-actin minus end change over time?
A) Decreases; decreases
B) Decreases; remains constant
C) Decreases; increases
D) Increases; decreases
E) Increases; remains constant

Question

Quizplus · Accepted Answer

The actin filaments at the leading edge form a web, the whole of which undergoes treadmilling. An incorporated actin in this web remains more or less immobile relative to the substratum, but is constantly moving away from the polymerizing plus end (and the membrane) and getting closer to the depolymerizing minus end.

Consider an Actin Subunit That Has Just Been Incorporated into an Actin