Caldesmon: Possible Functions in Microfilament Reorganization During Mitosis and Cell Transformation
Microfilaments are intimately involved in the morphological alterations observed both in cell transformation and mitosis. In both cases, microfilamenets show significant re-organization. While “normal” cells with well-spread morphologies have numerous bundles of microfilaments, transformed cells with rounded morphologies show dispersed microfilament patterns1. These changes in the structure of actin cables, as well as in substrate adhesion, are closely coupled with proliferation in both normal and transformed cells1, suggesting that the microfilament cytoskeleton may play an important role in oncogenic transformation. The process of cell division causes similar alterations in microfilament patterns to those seen in transformed cells. Microfilament bundles disassemble when cells become rounded-up during prophase2,3 resulting in a cytoarchitecture resembling the dispersed microfilament patterns seen in the many transformed cell types which exhibit rounded morphologies. Microfilament bundles that are anchored to focal contacts are also disrupted in both mitotic and transformed cells, causing reduced adhesion of such cells to their substrates. These observations suggest that cell transformation and cell division control are intimately related, not just superficially, but at the level of molecular control.
KeywordsCell Transformation Actin Binding Chicken Embryo Fibroblast Cdc2 Kinase Rounded Morphology
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