Double identity of SCAPER: A substrate and regulator of cyclin A/Cdk2

William Y. Tsang and Brian David Dynlacht

volume 7 | issue 6

15 March 2008
Pages: 702 - 705

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Cyclin A is a key regulator of DNA replication and mitosis, and cyclin A/Cdk2 activity is critical for progression of cells from G1/S to M phase of the cell cycle. There is abundant evidence that cyclin A is predominantly localized to, and functions in, the nucleus, and a number of nuclear cyclin A/Cdk2 substrates have been identified. Evidence supporting the presence of cyclin A and its associated activity in the cytoplasm have also been reported, but the biological significance of this cyclin/Cdk pool during cell cycle progression remains controversial. Recently, we identified and characterized a new cyclin A/Cdk2 substrate named SCAPER which is localized to the endoplasmic reticulum. By sequestering cyclin A/Cdk2, SCAPER is capable of directing the activity of this kinase complex away from the nucleus and regulating cyclin A/Cdk2 equilibrium in distinct subcellular compartments. This work paves new avenues for understanding the role of cytoplasmic cyclin A/Cdk2 and its potential contribution to cancer and tumor formation.

Authors

William Y. Tsang

New York University School of Medicine; New York, NY

Brian David Dynlacht