The retinoblastoma (RB) protein regulates cell proliferation and cell death. RB is cleaved by caspase during apoptosis. A mutation of the caspase-cleavage site in the RB C terminus has been made in the mouse Rb-1 locus; the resulting Rb-MI mice are resistant to endotoxin-induced apoptosis in the intestine. The Rb-MI mice do not exhibit increased tumor incidence, because the MI mutation does not...

The retinoblastoma tumor suppressor protein (RB), a critical mediator of cell cycle progression, is functionally inactivated in the majority of human cancers, including prostatic adenocarcinoma. The importance of RB tumor suppressor function in this disease is evident because 25% to 50% of prostatic adenocarcinomas harbor aberrations in RB pathway. However, no previous studies challenged the co...

The subcellular localization of the retinoblastoma (RB) protein has been studied in primate cell lines by immunofluorescence staining using different monoclonal and polyclonal antibodies. The protein appeared as granules of heterogeneous size over the interphase nuclei. Computer assisted digital overlap analysis indicated that it was predominantly localized in euchromatic areas with low DNA den...

Lung cancer is the leading cause of cancer deaths, accounting for more deaths than breast, colon, and prostate cancer combined. The retinoblastoma (Rb)/p16 tumor suppressive pathway is deregulated in most cancers. Loss of p16 occurs more frequently than Rb loss, suggesting that p16 suppresses cancer by regulating Rb as well as the related proteins p107 and p130. However, direct evidence demonst...

Methanolic extracts from 15 medicinal plants representing 11 families, used traditionally for malaria treatment in Kenya were screened for their in vivo antimalarial activity in mice against a chloroquine (CQ)-tolerant Plasmodium berghei NK65, either alone or in combination with CQ. The plant parts used ranged from leaves (L), stem bark (SB), root bark (RB), seeds (S) and whole plant (W). When ...

The real-time dynamics of photoexcited and photoionized rubidium (Rb) atoms attached to helium (He) nanodroplets is studied by femtosecond pump-probe mass spectrometry. While excited Rb atoms in the perturbed 6p-state (Rb*) desorb off the He droplets, Rb(+) photoions tend to sink into the droplet interior when created near the droplet surface. The transition from Rb(+) solvation to full Rb* des...

Inactivation of the retinoblastoma protein (Rb) has a key role in tumorigenesis. It is well established that Rb function is largely regulated by a dynamic balance of phosphorylation and dephosphorylation. Although much research has been done to understand the mechanisms and function of RB phosphorylation, the regulation of Rb dephosphorylation is still not well understood. In this study, we dem...

The recent finding that the Retinoblastoma protein (Rb) is able to regulate apoptosis in a non-transcriptional manner directly at the mitochondria by interaction with the pro-apoptotic protein Bax prompted this investigation of the complex formed between Rb and Bax. Because the function of Rb in the cellular processes of proliferation, apoptosis, senescence and differentiation is regulated by p...

The E7 oncoprotein of human papillomavirus type 16 promotes cell proliferation in the presence of antiproliferative signals. Mutagenesis of E7 has revealed that this activity requires three regions, conserved regions 1 and 2 and a C-terminal zinc finger. Binding to the retinoblastoma tumor repressor (Rb) through an LxCxE motif in conserved region 2 is necessary, but not sufficient, for E7 to in...

Sphingosine kinase isoform 1 (SK1) inhibitors may serve as therapeutic agents for proliferative diseases, including hypertension. We synthesized a series of sphingosine-based SK1-selective inhibitors, the most potent of which is RB-005 (IC(50) = 3.6 μM), which also induced proteasomal degradation of SK1 in human pulmonary arterial smooth muscle cells.