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Updated: Jul 20, 2026

Genome-wide Protein-protein Interaction Screening by Protein-fragment Complementation Assay (PCA) in Living Cells
Published on: March 3, 2015
Requirement of the prolyl isomerase Pin1 for the replication checkpoint
K E Winkler1, K I Swenson, S Kornbluth
1Department of Pharmacology and Cancer Biology, Duke University Medical Center, Box 3813, Durham, NC 27710, USA.
Abstract:
The peptidyl-prolyl isomerase Pin1 has been implicated in regulating cell cycle progression. Pin1 was found to be required for the DNA replication checkpoint in Xenopus laevis. Egg extracts depleted of Pin1 inappropriately transited from the G2 to the M phase of the cell cycle in the presence of the DNA replication inhibitor aphidicolin. This defect in replication checkpoint function was reversed after the addition of recombinant wild-type Pin1, but not an isomerase-inactive mutant, to the depleted extract. Premature mitotic entry in the absence of Pin1 was accompanied by hyperphosphorylation of Cdc25, activation of Cdc2/cyclin B, and generation of epitopes recognized by the mitotic phosphoprotein antibody, MPM-2. Therefore, Pin1 appears to be required for the checkpoint delaying the onset of mitosis in response to incomplete replication.
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