Polo box domain of Plk3 functions as a centrosome localization signal, overexpression of which causes mitotic arrest, cytokinesis defects, and apoptosis.
Polo-like kinase 3 (Plk3), an immediate early response gene product, plays an important role in the regulation of mitosis, DNA damage checkpoint activation, and Golgi dynamics. Similar to other members of the Plk family, Plk3 has a conserved kinase domain at the N terminus and a Polo box domain consisting of two Polo boxes at the C terminus. In this study, we demonstrate that the Polo box domain of Plk3 is sufficient for subcellular localization of this kinase to the centrosomes, the spindle poles, and the midbody when ectopically expressed in HeLa and U2OS cells. Both Polo boxes are required for the subcellular localization. Overexpression of the Polo box domain, not the kinase domain, of Plk3 causes significant cell cycle arrest and cytokinesis defects, eventually leading to mitotic catastrophe/apoptosis. Interestingly, the Polo box domain of Plk3 is more potent in inhibiting cell proliferation and inducing apoptosis than that of Plk1, suggesting that this domain can provide an additional structural basis for discovery of new anticancer drugs given the current emphasis on Plk1 as a therapeutic target.
Division of Molecular Carcinogenesis, Department of Medicine, New York Medical College, Basic Science Building, Valhalla, NY 10595, USA.
Ning
N
Jiang
Xiaoxing
X
Wang
Meena
M
Jhanwar-Uniyal
Zbigniew
Z
Darzynkiewicz
Wei
W
Dai
D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D018797:Cell Cycle Proteins / Q000378:metabolism / Q000502:physiology; D045744:Cell Line, Tumor; D018385:Centrosome / Q000378:metabolism / Q000648:ultrastructure*; D048749:Cytokinesis; D004247:DNA / Q000737:chemistry; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D008938:Mitosis; D008957:Models, Genetic; D009154:Mutation; D009369:Neoplasms / Q000378:metabolism; D019913:Nuclear Localization Signals; D010957:Plasmids / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism / Q000502:physiology; D013997:Time Factors; D014162:Transfection; D025521:Tumor Suppressor Proteins; D000097869:Polo-Like Kinase 1; D000097868:Polo-like Kinases
D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D004247:DNA; D049452:Green Fluorescent Proteins; D019913:Nuclear Localization Signals; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D000097869:Polo-Like Kinase 1; C486256:PLK3 protein, human; D000097868:Polo-like Kinases