Establishment of spindle bipolarity is pivotal for proper chromosome segregation and mitotic progression. Mammalian polo-like kinase 1 (Plk1) has been thought to play a central role in this process. However, how Plk1 contributes to this event remains unknown. Here we demonstrated that Cdc2-dependent phosphorylation on a gamma-TuRC recruitment protein, Nedd1/GCP-WD, at two distinct sites provides both temporal and spatial cues to timely bring about Plk1 functions to the centrosomes and spindles via phosphorylation-dependent interaction with the polo-box domain of Plk1. At centrosomes, Plk1 interacted with a C-terminal phosphorylated motif of Nedd1 to phosphorylate the latter, a step suggested to be important for centrosome-based microtubule nucleation. Immediately following this event, Plk1 also interacted with an N-terminal phosphorylated motif of Nedd1 along the spindles and phosphorylated an Augmin subunit, Hice1, to promote microtubule-based microtubule nucleation. Loss of Nedd1-mediated Hice1 phosphorylation by Plk1 resulted in impaired Augmin interaction with microtubules and diminished gamma-tubulin recruitment to the spindles that ultimately led to defects in proper bipolar spindle formation and chromosome segregation. Taken together, the data provided here demonstrate the underlying mechanisms of how the two distinct Plk1-Nedd1 interactions at the centrosomes and spindles are deciphered into different biochemical and cellular outcomes to achieve normal bipolar spindle formation and mitotic progression. This study may allow us to understand the underlying mechanism of how Plk1 cooperates with other mitotic components to promote timely activation of specific protein complexes at distinct subcellular structures. Aside from the role of Plk1 in the regulation of Nedd1 at centrosomes, we have been focusing on understanding the physiological significance of the Cep192-Plk1 interaction. Our results showed that Plk1 binds to the phosphorylated S995 motif of Cep192. To better understand the significance of this event, we have generated cells expressing a phosphorylation-defective Cep192 S995A mutant. Characterization of this mutant is underway. Preliminary results suggests that the p-S995-dependent interaction between Cep192 and Plk1 is important for proper establishment of spindle bipolarity during M-phase of the cell cycle. In depth analysis of the Cep192 S995A mutant-expressing cells may allow us to comprehend how Aurora A influences the function of Plk1, vice versa.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIABC011324-05
Application #
8938059
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
5
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Basic Sciences
Department
Type
DUNS #
City
State
Country
Zip Code
Lim, Jung Mi; Lee, Kyung S; Woo, Hyun Ae et al. (2015) Control of the pericentrosomal H2O2 level by peroxiredoxin I is critical for mitotic progression. J Cell Biol 210:23-33
Park, Chi Hoon; Park, Jung-Eun; Kim, Tae-Sung et al. (2015) Mammalian Polo-like kinase 1 (Plk1) promotes proper chromosome segregation by phosphorylating and delocalizing the PBIP1·CENP-Q complex from kinetochores. J Biol Chem 290:8569-81
Meng, Lingjun; Park, Jung-Eun; Kim, Tae-Sung et al. (2015) Bimodal Interaction of Mammalian Polo-Like Kinase 1 and a Centrosomal Scaffold, Cep192, in the Regulation of Bipolar Spindle Formation. Mol Cell Biol 35:2626-40
Lee, Miseon; Chang, Jaerak; Chang, Sunghoe et al. (2014) Asymmetric spindle pole formation in CPAP-depleted mitotic cells. Biochem Biophys Res Commun 444:644-50
Lee, Kyung S; Park, Jung-Eun; Kang, Young Hwi et al. (2014) Mechanisms underlying Plk1 polo-box domain-mediated biological processes and their physiological significance. Mol Cells 37:286-94
González-Sancho, José M; Greer, Yoshimi Endo; Abrahams, Cristina L et al. (2013) Functional consequences of Wnt-induced dishevelled 2 phosphorylation in canonical and noncanonical Wnt signaling. J Biol Chem 288:9428-37
Zou, Jianqiu; Rezvani, Khosrow; Wang, Hongmin et al. (2013) BRCA1 downregulates the kinase activity of Polo-like kinase 1 in response to replication stress. Cell Cycle 12:
Chang, Jaerak; Seo, Sang Gwon; Lee, Kyung Ho et al. (2013) Essential role of Cenexin1, but not Odf2, in ciliogenesis. Cell Cycle 12:655-62
Lee, Kyung Ho; Johmura, Yoshikazu; Yu, Li-Rong et al. (2012) Identification of a novel Wnt5a-CK1ýý-Dvl2-Plk1-mediated primary cilia disassembly pathway. EMBO J 31:3104-17
Kang, Young H; Park, Chi Hoon; Kim, Tae-Sung et al. (2011) Mammalian polo-like kinase 1-dependent regulation of the PBIP1-CENP-Q complex at kinetochores. J Biol Chem 286:19744-57

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