Role of Calmodulin in Cadmium-induced Microtubule Disassembly

Micromolar CdCl2 has been shown to cause disassembly of the cytoplasmic microtubule complex in cultured Swiss 3T3 cells. We show in this paper that Cd(II), an environmental and occupational health hazard, induces microtubule disassembly in an in situ cytoskeleton model system, and that the calmodulin inhibitors, trifluoperazine and Compound 48/80, prevent this Cd(II)-induced microtubule disassembly. Our results suggest that Cd(II) affects microtubules by activating calmodulin associated with the cytoskeleton. Furthermore, the fact that these two ions have very similar ionic radii (0.99A vs. 0.97A) supports our conclusion that Cd(II) acts similarly to Ca(II) in inducing microtubule disassembly. This may be relevant to the mechanism of Cd-mediated cellular injury.