OBJECTIVE To explore the expression of A-kinase anchor protein 95 (AKAP95), Cyclin D1, Cyclin E1, and Connexin43 (Cx43) in rectal cancer tissues and assess the associations between each of the proteins and pathological parameters, as well as their inter-relationships. METHODS AKAP95, Cyclin D1, Cyclin E1, and Cx43 protein expression rates were evaluated by immunohistochemistry in 50 rectal ca...

Rearrangement and amplification of the D-type cyclin genes have been reported in human cancer. Previous studies have demonstrated that Ras-mediated skin tumorigenesis depends on pathways that act through cyclin D1 and D2; however, the role of cyclin D3 remains unknown. The present study demonstrates that cyclin D3 ablation does not affect keratinocyte proliferation, but instead increases apopto...

The timing mechanism for mitotic progression is still poorly understood. The spindle assembly checkpoint (SAC), whose reversal upon chromosome alignment is thought to time anaphase [1-3], is functional during the rapid mitotic cycles of the Drosophila embryo; but its genetic inactivation had no consequence on the timing of the early mitoses. Mitotic cyclins-Cyclin A, Cyclin B, and Cyclin B3-inf...

Purified cyclin B-cdc2 kinase has been shown previously to trigger cyclin degradation in interphase frog extracts by initiating a cascade of reactions that includes cyclin ubiquitinylation and ends with proteolysis. However, cyclin A-cdc2 kinase was not assayed in these early experiments. Here we have shown that full-length recombinant human cyclin A failed to induce cyclin degradation when it ...

Cyclin-dependent kinase 4 (CDK4)/cyclin D complexes are expressed early in the G(1) phase of the cell cycle and stimulate the expression of genes required for G(1) progression by phosphorylation of the product of the retinoblastoma gene, pRb. To elaborate the molecular pathway of CDK4 activation and substrate selection we have determined the structure of nonphosphorylated CDK4/cyclin D3. This s...

The entry into mitosis is dependent on the activation of mitotic forms of cdc2 kinase. In many cell types, cyclin A-associated kinase activity peaks just prior to that of cyclin B, although the precise role of cyclin A-associated kinase in the entry into mitosis is still unclear. Previous work has suggested that while cyclin B is capable of triggering cyclin destruction in Xenopus cell-free sys...

Here we have used siRNAs and time-lapse epifluorescence microscopy to examine the roles of various candidate mitotic cyclins in chromatin condensation in HeLa cells. Knocking down cyclin A2 resulted in a substantial (∼7 h) delay in chromatin condensation and histone H3 phosphorylation, and expressing an siRNA-resistant form of cyclin A2 partially rescued chromatin condensation. There was no det...

The expression of retinoblastoma (pRb) and cyclin D3 proteins is highly induced during the process of skeletal myoblast differentiation. We have previously shown that cyclin D3 is nearly totally associated with hypophosphorylated pRb in differentiated myotubes, whereas Rb-/- myocytes fail to accumulate the cyclin D3 protein despite normal induction of cyclin D3 mRNA. Here we report that pRb pro...

Cyclin E2, but not cyclin E1, is included in several gene signatures that predict disease progression in either tamoxifen-resistant or metastatic breast cancer. We therefore examined the role of cyclin E2 in antiestrogen resistance in vitro and its potential for therapeutic targeting through cyclin-dependent kinase (CDK) inhibition. High expression of CCNE2, but not CCNE1, was characteristic of...

To elucidate carcinogenesis in the endometrium, we investigated cyclin D1 immunoreactivities in 20 normal endometria, 20 endometrial hyperplasias and 141 endometrioid-type endometrial adenocarcinoma. We also evaluated the correlation of cyclin D1 expression with Ki-67, cyclin E, cyclin A, cdk2, p27 and p53, and clinicopathological parameters and prognosis. Cyclin D1 expression increased signifi...