Human PF4 is a heparin-binding chemokine known to be capable of inhibiting endothelial cell proliferation and angiogenesis. To explore the biological mechanisms responsible for this action, we investigated the effect of PF4 on epidermal growth factor (EGF)-stimulated human umbilical vein endothelial cells (HUVEC), a model system in which stimulation is essentially independent of interaction wit...

BACKGROUND Leishmania species are parasitic protozoa that have a tightly controlled cell cycle, regulated by cyclin-dependent kinases (CDKs). Cdc2-related kinase 3 (CRK3), an essential CDK in Leishmania and functional orthologue of human CDK1, can form an active protein kinase complex with Leishmania cyclins CYCA and CYC6. Here we describe the identification and synthesis of specific small mole...

In this study, we isolated and characterized a human cyclin A-like gene that we named cyclin A1. Cyclin A1 has 48% identity with human cyclin A and is more related to the recently cloned murine cyclin A1 (84% identity). The human cyclin A1 is specifically expressed in testis and brain among all of the normal tissues that we studied by Northern blot analysis; in addition, it is expressed in seve...

The rational development of specific inhibitors for the approximately 500 protein kinases encoded in the human genome is impeded by a poor understanding of the structural basis for the activity and selectivity of small molecules that compete for ATP binding. Combining classical dynamic simulations with a novel ab initio computational approach linear-scalable to molecular interactions involving ...

Induction of a G1 phase cell cycle arrest, caused primarily by the inhibition of cyclin-dependent-kinase 2 (cdk2), is a critical step in the differentiation of myoblasts into myotubes. Here, we report that two microRNAs, miR-322/424 and miR-503, are induced and promote cdk2 inhibition during myogenesis. These microRNAs down-regulate Cdc25A, the phosphatase responsible for removing inhibitory ph...

Cisplatin cytotoxicity is dependent on cyclin-dependent kinase 2 (Cdk2) activity in vivo and in vitro. A Cdk2 mutant (Cdk2-F80G) was designed in which the ATP-binding pocket was altered. When expressed in mouse kidney cells, this protein was kinase inactive, did not inhibit endogenous Cdk2, but protected from cisplatin. The mutant was localized in the cytoplasm, but when coexpressed with cyclin...

We investigated the function of cyclin-dependent kinase 2 (Cdk2) in neural progenitor cells during postnatal development. Chondroitin sulfate proteoglycan (NG2)-expressing progenitor cells of the subventricular zone (SVZ) show no significant difference in density and proliferation between Cdk2(-/-) and wild-type mice at perinatal ages and are reduced only in adult Cdk2(-/-) mice. Adult Cdk2(-/-...

R-Phycoerythrin (R-PE), one of the chemical constituents of red algae, could produce singlet oxygen upon excitation with the appropriate radiation and possibly be used in photodynamic therapy (PDT) for cancer. Documents reported that R-PE could inhibit cell proliferation in HepG2 and A549 cells, which was significative for cancer therapy. This is due to the fact that R-PE could kill cancer cell...

Prolactinomas are the most common pituitary tumors. The mechanisms of cell-cycle regulators underlying their invasive biological behavior and poor prognosis have not yet been fully clarified. We classified 48 human prolactinomas as invasive or non-invasive and determined cyclin D1, cyclin E1, p16, p27, Cdk2 and Cdk4 expression by immunohistochemistry analysis of tissue microarray constructs. Th...

Staurosporine (ST), a protein kinase inhibitor, at a concentration of 20 nM arrests normal diploid fibroblasts 3 h into G1 (H. A. Crissman et al., Proc. Natl. Acad. Sci. USA, 88: 7580-7584, 1991; K. Abe et al., Exp. Cell Res., 192: 122-127, 1991). ST (2 nM) induces a new G1 arrest point at 6 h into G1. Partial phosphorylation of the retinoblastoma protein was observed at the 2 nM ST arrest poin...