[Frontiers in Bioscience S4, 639-650, January 1, 2012]

14-3-3zeta cooperates with Phosphorylated Plk1 and is required for correct cytokinesis

Jian Du 1, Lijian Chen2, Xin Luo1, Yuxian Shen3, Zhen Dou4, Jilong Shen5, Li Cheng1, Ying Chen3, Chengjin Li3, Hua Wang6, Xuebiao Yao4

1Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei 230032, China, 2Department of Anaesthesiology, the First Affiliated Hospital of Anhui Medical University, Hefei 230032, China,3Key Laboratory of Gene Resource Utilization for Genetic Diseases of Educational Ministry and Anhui Province, Anhui Medical University,4Anhui Provincial Key Laboratory for Cellular Dynamics and Chemical Biology, Hefei 230027, China, 5Department of Microbiology and Parasitology, Anhui Provincial Key Laboratory of Genomic Research, Anhui Medical University, Hefei 230032, China, 6 Department of Oncology, Anhui Provincial Hospital, Hefei 230001, China

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
4. Results
4.1. Subcellular localization of 14-3-3 isoforms in cell cycle
4.2. Plk1 is a novel 14-3-3 binding protein
4.3. Evidence for the interaction between Plk1 and 14-3-3zeta in vivo
4.4. Phosphorylation of Plk1 at S330/597 Enhances 14-3-3zeta Binding
4.5. Ectopic expression of the plk1 phosphorylation mutants, S330/597A induces cytokinesis failure
5. Discussion
6. Acknowledgment
7. References

1. ABSTRACT

Proteins of the 14-3-3 family are functionally conserved in eukaryotic kingdom which participates in diversified and critical cellular processes. However, the exact roles of these proteins in mitotic regulation has remained elusive. Polo-like kinase 1 (Plk1) is a serine/threonine protein kinase that plays multiple critical functions such as centrosome maturation, mitotic chromosome segregation, cytokinesis, and the DNA damage response. Here we show that 14-3-3zeta interacts and cooperates with Plk1 in mitotic progress. 14-3-3zeta is associated with the spindle at metaphase and concentrated in the midbody during cytokinesis. Using yeast two hybrid assay, we found a functional connection between 14-3-3zeta and Plk1. We demonstrate that phosphorylation of Plk1 at S330 and S597 promotes its interaction with 14-3-3zeta. Importantly, 14-3-3zeta cooperates with Plk1 in ensuring successful cytokinesis. We conclude that mitotic phosphorylation of Plk1 promotes interaction with 14-3-3zeta and this interaction is required for faithful cytokinesis. Taken together with the results of previous studies, our results suggest 14-3-3 family emerges as a novel player in mitotic regulation: cooperation with Plk1 to ensure a faithful cytokinesis.