Flux of Membrane Components during Cytokinesis

Wang et al., J. Cell Biol. 127:963-971 (1994)

Fishkind et al., J. Cell Sci. 109:2041-2051 (1996)

Many membrane components are linked to the underlying actin cortex. Their movements thus reflect the dynamics of the associated cytoskeleton. Fluorescent latex beads were used to tag membrane components and detect their dynamics during cytokinesis.

Movement of Surface Components during Normal Cytokinesis

After anaphase onset, surface bound beads start to move toward the equator. Many beads show a surge in movement upon the passage of chromosomes, suggesting possible direct or indirect linkage between chromosomes and the cortex. Recording time, 10 min.

Effects of Cytochalasin on the Movement of Surface Components

When cells are treated with cytochalasin D to disrupt actin filaments after anaphase onset, the beads change their pattern of movement and form random clusters. Many of them reverse the direction, moving away from the equator, suggesting counter-balancing forces throughout the cortex. Recording time, 7 min.

Effects of Nocodazole on the Movement of Surface Components

Directional movement of beads stops when cells are treated with nocodazole to disassemble microtubules after the onset of anaphase, suggesting that microtubules may mediate the delivery of signals for cortical transport. This example shows the most uniform behavior. In other cells the responses are more variable, which may reflect the increasing resistance of midzone microtubules to nocodazole or the transient requirement of signals for cortical movement. Recording time, 9 min.

Effects of Taxol on the Movement of Surface Components

When cells are treated with taxol to stabilize microtubules and induce microtubule reorganization after anaphase onset, bead movement shows a striking fountain pattern. The converging paths toward the center of the cell appear to follow the distribution of the distal ends of microtubules. Recording time, 18 min.