Periodic activity of the anaphase-promoting complex (APC) ubiquitin ligase determines progression through multiple cell cycle transitions by targeting cell cycle regulators for destruction. At the G(1)/S transition, phosphorylation-dependent dissociation of the Cdh1-activating subunit inhibits the APC, allowing stabilization of proteins required for subsequent cell cycle progression. Cyclin-dep...

Inactivation of Cyclin E-Cdk2 is essential for a timely arrest of the epidermal cell proliferation program during Drosophila embryogenesis. E-type cyclin-cdk complexes are thought to be activated by D-types titrating away inhibitors and inducing cyclin E transcription by activating E2F transcription factors via Rb phosphorylation. Therefore, we have analyzed whether the developmentally controll...

Cyclin E plays a pivotal role in the regulation of G1-S transition and relates to malignant transformation of cells. However, the clinical significance of cyclin E in patients with laryngeal squamous cell carcinoma (LSCC) remains unknown. We examined the expression of cyclin E in 102 patients with LSCC and analyzed its relation to clinicopathological parameters, cell proliferation, and clinical...

There is increasing evidence that p21(Cip1) and p27(Kip1) are requisite positive regulators of cyclin D1.CDK4 assembly and nuclear accumulation. Both Cip and Kip proteins can promote nuclear accumulation of cyclin D1, but the underlying mechanism has not been elucidated. We now provide evidence that p21(Cip1) promotes the nuclear accumulation of cyclin D1 complexes via inhibition of cyclin D1 n...

Cyclin A1 belongs to the type-A cyclins and participates in cell cycle regulation. Since its discovery, cyclin A1 has been shown mostly in testis. It plays important roles in spermatogenesis. However, there were also reports on ovary expression of cyclin A1. Therefore, we intended to revisit the expression of cyclin A1 in mouse ovary. Our study showed that cyclin A1 was expressed at the mRNA le...

UNLABELLED Deregulation of cell cycle control is a hallmark of cancer. The primary cyclins (A, B1, D1, D3 and E) are crucial for cell cycle progression. Secondary cyclins (C and H) have putative indirect effects on cell cycle propulsion and are not previously evaluated in breast cancer. We have examined protein expression and gene amplification of cyclins in breast carcinomas and correlated the...

The cyclin-dependent protein kinases (CDKs) are activated by association with cyclins and by phosphorylation at a conserved threonine residue by the CDK-activating kinase (CAK). We have studied the binding of various human CDK and cyclin subunits in vitro, using purified proteins derived from baculovirus-infected insect cells. We find that most CDK-cyclin complexes known to exist in human cells...

Cyclin D1b is one of two proteins translated from cyclin D1 transcripts (isoforms a and b) that are generated due to gene polymorphism. Our previous study has reported low cyclin D1b expression in cervical cancer tissue, with an expression level in moderately or poorly differentiated tissues that was significantly lower than that in well-differentiated tissues. However, the functional role of c...

The human CCND1 gene, which encodes the cell-cycle protein cyclin D1, is one of the most frequently amplified genes in human cancers. Cyclin D1 activates the cyclin-dependent kinases CDK4 and CDK6 and drives cell proliferation. Beyond the cell-cycle role, the full repertoire of cyclin D1 functions in cancer cells is still unclear. Emerging evidence indicates that cyclin D1 may play a role in DN...

INTRODUCTION Lung cancer is a major cause of mortality and morbidity worldwide. Galectin-3 is multifunctional protein, which is involved in regulation of cell growth, cell adhesion, cell proliferation, angiogenesis and apoptosis. Cyclin D1 together with other cyclin plays an important role in cell cycle control. Cyclin D1 regulates the G1-to-S phase transition. The aim of this study was the eva...