Fig. 4. Perturbation of any single cytoskeletal system in rapidly frozen, fixed samples does not prevent interaction of the remaining two. Triple label confocal micrographs showing that inhibition of microtubule polymerization (nocodazole) does not prevent association of cytokeratin (blue) with F-actin (green, arrowheads). Inhibition of F-actin polymerization (latrunculin) fails to prevent cytokeratin (blue) from associating with aster microtubules (red, arrowheads). However, most of the cytokeratin is found in large aggregates on the substrate (arrow). Inhibition of cytokeratin polymerization (C11) does not inhibit F-actin association with aster microtubules (arrowheads). However, microtubules were found in small bundles on the substrate rather than as large asters. Inhibition of both microtubule and latrunculin polymerization (noc/lat) resulted in cytokeratin forming large, unorganized aggregates.