Cyclin A- and Cyclin E-Cdk Complexes Shuttle between the Nucleus and the Cytoplasm

AUTOR(ES)

Jackman, Mark

FONTE

The American Society for Cell Biology

RESUMO

Cyclins A and E and their partner cyclin-dependent kinases (Cdks) are key regulators of DNA synthesis and of mitosis. Immunofluorescence studies have shown that both cyclins are nuclear and that a proportion of cyclin A is localized to sites of DNA replication. However, recently, both cyclin A and cyclin E have been implicated as regulators of centrosome replication, and it is unclear when and where these cyclin-Cdks can interact with cytoplasmic substrates. We have used live cell imaging to study the behavior of cyclin/Cdk complexes. We found that cyclin A and cyclin E are able to regulate both nuclear and cytoplasmic events because they both shuttle between the nucleus and the cytoplasm. However, we found that there are marked differences in their shuttling behavior, which raises the possibility that cyclin/Cdk function could be regulated at the level of nuclear import and export. In the course of these experiments, we have also found that, contrary to published results, mutations in the hydrophobic patch of cyclin A do affect Cdk binding and nuclear import. This has implications for the role of the hydrophobic patch as a substrate selection motif.

Documentos Relacionados

• A- and B-type cyclins differentially modulate substrate specificity of cyclin-cdk complexes.
• Altered regulation of G1 cyclins in senescent human diploid fibroblasts: accumulation of inactive cyclin E-Cdk2 and cyclin D1-Cdk2 complexes.
• Functional Interaction between the Bovine Papillomavirus Virus Type 1 Replicative Helicase E1 and Cyclin E-Cdk2†
• Estrogen-dependent cyclin E-cdk2 activation through p21 redistribution.
• Activation of cyclin E/CDK2 is coupled to site-specific autophosphorylation and ubiquitin-dependent degradation of cyclin E.