Human cytomegalovirus infection results in altered Cdk2 subcellular localization

Human cytomegalovirus (HCMV) stimulates numerous cellular pathways upon infection. One of these pathways involves activation of cyclin E/Cdk2. Recent reports have demonstrated that Cdk2 is retained in the cytoplasm of cells arrested in GO by serum deprivation, sequestered from its regulatory subunit cyclin E which is located within the nucleus. Cdk2 rapidly enters the nucleus and becomes active upon stimulation of these cells with serum growth factors. The ability of HCMV to activate cyclin E/Cdk2 in both serum-arrested cells and contact-inhibited cells suggests that HCMV infection may also result in the translocation of Cdk2 into the nucleus. In this report, we demonstrate that Cdk2 is sequestered in the cytoplasm of cells arrested in GO by contact inhibition, as well as those arrested by serum deprivation. HCMV infection results in translocation of Cdk2 from the cytoplasm into the nucleus within 24 h of infection, both in serum-arrested and contact-inhibited cells.