Colchicine activates actin polymerization by microtubule depolymerization

• Published in: Molecules and cells Vol. 7; no. 3; p. 431
• Main Authors: Jung, H I, Shin, I, Park, Y M, Kang, K W, Ha, K S
• Format: Journal Article
• Language: English
• Published: United States 30-06-1997
• Subjects: 3T3 Cells; Actins - metabolism; Animals; Biopolymers - chemistry; Biopolymers - metabolism; Cell Line; Colchicine - pharmacology; Enzyme Activation - drug effects; Enzyme Inhibitors - pharmacology; Marine Toxins; Mice; Microtubules - chemistry; Microtubules - drug effects; Microtubules - metabolism; Okadaic Acid - pharmacology; Oxazoles - pharmacology; Phospholipase D - metabolism; Phosphoprotein Phosphatases - antagonists & inhibitors; Phosphorylation; Protein Kinase C - metabolism; Rats; Serine - metabolism; Threonine - metabolism; Type C Phospholipases - metabolism
• ISSN: 1016-8478
• DOI: 10.1016/S1016-8478(23)13317-6

Swiss 3T3 fibroblasts were treated with the microtubule-disrupting agent colchicine to study any interaction between microtubule dynamics and actin polymerization. Colchicine increased the amount of filamentous actin (F-actin), in a dose- and time-dependent manner with a significant increase at 1 h by about 130% over control level. Confocal microscopic observation showed that colchicine increased F-actin contents by stress fiber formation without inducing membrane ruffling. Colchicine did not activate phospholipase C and phospholipase D, whereas lysophosphatidic acid did, indicating that colchicine may have a different mechanism of actin polymerization regulation from LPA. A variety of microtubule-disrupting agents stimulated actin polymerization in Swiss 3T3 and Rat-2 fibroblasts as did colchicine, but the microtubule-stabilizing agent taxol inhibited actin polymerization induced by the above microtubule-disrupting agents. In addition, colchicine-induced actin polymerization was blocked by two protein phosphatase inhibitors, okadaic acid and calyculin A. These results suggest that microtubule depolymerization activates stress fiber formation by serine/threonine dephosphorylation in fibroblasts.