Cell cycle arrest and apoptosis induced by human Polo-like kinase 3 is mediated through perturbation of microtubule integrity.
Human Polo-like kinase 3 (Plk3, previously termed Prk or Fnk) is involved in regulation of cell cycle progression through the M phase (B. Ouyang, H. Pan, L. Lu, J. Li, P. Stambrook, B. Li, and W. Dai, J. Biol. Chem. 272:28646-28651, 1997). Here we report that in most interphase cells endogenous Plk3 was predominantly localized around the nuclear membrane. Double labeling with Plk3 and gamma-tubulin, the latter a major component of pericentriole materials, revealed that Plk3 was closely associated with centrosomes and that its localization to centrosomes was dependent on the integrity of microtubules. Throughout mitosis, Plk3 appeared to be localized to mitotic apparatus such as spindle poles and mitotic spindles. During telophase, a significant amount of Plk3 was also detected in the midbody. Ectopic expression of Plk3 mutants dramatically changed cell morphology primarily due to their effects on microtubule dynamics. Expression of a constitutively active Plk3 (Plk3-A) resulted in rapid cell shrinkage, which led to formation of cells with an elongated, unsevered, and taxol-sensitive midbody. In contrast, cells expressing a kinase-defective Plk3 (Plk3(K52R)) mutant exhibited extended, deformed cytoplasmic structures, the phenotype of which was somewhat refractory to taxol treatment. Expression of both Plk3-A and Plk3(K52R) induced apparent G(2)/M arrest followed by apoptosis, although the kinase-defective mutant was less effective. Taken together, our studies strongly suggest that Plk3 plays an important role in the regulation of microtubule dynamics and centrosomal function in the cell and that deregulated expression of Plk3 results in cell cycle arrest and apoptosis.
Wang
Qi
Q
Department of Medicine and Brander Cancer Research Institute, New York Medical College, Hwathorne, 10532, USA.
Xie
Suqing
S
Chen
Jie
J
Fukasawa
Kenji
K
Naik
Ulhas
U
Traganos
Frank
F
Darzynkiewicz
Zbigniew
Z
Jhanwar-Uniyal
Meena
M
Dai
Wei
W
D017209:Apoptosis / Q000502:physiology*; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002458:Cell Fractionation; D048429:Cell Size; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008870:Microtubules / Q000378:metabolism*; D009685:Nuclear Envelope / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D008941:Spindle Apparatus / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins; D000097869:Polo-Like Kinase 1; D000097868:Polo-like Kinases
D018797:Cell Cycle Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D000097869:Polo-Like Kinase 1; C486256:PLK3 protein, human; D000097868:Polo-like Kinases