Centrosomal Localization Of Rhogdi Beta And Its Relevance To Mitotic Processes In Cancer Cells

Rho GDP-dissociation inhibitors (RhoGDIs) are regulators of Rho family GTPases. RhoGDI beta has been implicated in cancer progression, but its precise role remains unclear. We determined the subcellular localization of RhoGDI beta and examined the effects of its overexpression and RNAi knockdown in cancer cells. Immunofluorescence staining showed that RhoGDI beta localized to centrosomes in human cancer cells. In He La cells, exogenous OFF-tagged RhoGDI beta localized to centrosomes and its overexpression caused prolonged mitosis and aberrant cytokinesis in which the cell shape was distorted. RNAi knockdown of RhoGDI beta led to increased incidence of monopolar spindle mitosis resulting in polyploid cells. These results suggest that RhoGDI beta has mitotic functions, including regulation of cytokinesis and bipolar spindle formation. The dysregulated expression of RhoGDI beta may contribute to cancer progression by disrupting these processes.