D4-GDI belongs to the family of Rho-GDIs or GDP-dissociation inhibitors for the Rho/Rac family of small G proteins； consisting of RhoGDI-1， D4 GDI/RhoGDI-2 and RhoGDI-3. It inhibits the release of GDP from the Rho proteins， essential for GTP-loading and activation of GTPase activity. D4-GDI is located in the cytoplasm and is involved in the regulation of the membrane association and dissociation cycle of Rho/Rac proteins. It is known to be a substrate for caspase 3 during Fas-mediated apoptosis.
D4-GDI is expressed only in hematopoietic tissues， mainly in B and T cells， unlike RhoGDI which is expressed ubiquitously. D4-GDI plays a role in the regulation of lymphocyte activation， survival， and responsiveness. Expression of D4-GDI is also observed in cells of nonhematopoietic neoplasms， including ovarian and bladder cancer cells， suggestive of D4-GDI’s role in progression of human tumors. D4-GDI is expressed in human breast cancer cells. In different human breast cancer cell lines that were studied， cell lines with high invasive activities， for example MDA-MB-231， expressed higher D4-GDI than did weakly invasive and noninvasive cell lines. Intentional disruption of D4-GDI by steadily expressing small interfering RNA （siRNA） against D4-GDI transcripts successfully blocks the motility and invasive potential of MDA-MB-231 cells in vitro. Cells deficient of D4-GDI revert to a normal breast epithelial phenotype characterized by the formation of cysts with a central lumen when grown on Matrigel. D4-GDI reduction is linked to a down-regulation of the cell surface protein ?1-integrin and a loss of cell-matrix adhesion， suggestive of D4-GDI induction of cell invasion by controlling ?1-integrin expression. The expression of ?1-integrin and invasive activities are restored once there’s restitution of D4-GDI expression to the levels found in the parental MDA-MB-231 cells. Therefore it is suggested that D4-GDI may play a significant role in the regulation of breast cancer cell invasiveness.
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來源宿主
大腸桿菌中重組表達
溶解建議
Sterile Filtered clear solution. D4-GDI protein in 50mM Tris-acetate， pH7.5， 20% glycerol and 1mM EDTA.
保存建議
Store vial at -20℃ to -80℃. When stored at the recommended temperature， this protein is stable for 12 months.
Please prevent freeze-thaw cycles.
