CCT chaperonin complex is required for the biogenesis of functional Plk1.
Experiments from several different organisms have demonstrated that polo-like kinases are involved in many aspects of mitosis and cytokinesis. Here, we provide evidence to show that Plk1 associates with chaperonin-containing TCP1 complex (CCT) both in vitro and in vivo. Silencing of CCT by use of RNA interference (RNAi) in mammalian cells inhibits cell proliferation, decreases cell viability, causes cell cycle arrest with 4N DNA content, and leads to apoptosis. Depletion of CCT in well-synchronized HeLa cells causes cell cycle arrest at G(2), as demonstrated by a low mitotic index and Cdc2 activity. Complete depletion of Plk1 in well-synchronized cells also leads to G(2) block, suggesting that misfolded Plk1 might be responsible for the failure of CCT-depleted cells to enter mitosis. Moreover, partial depletion of CCT or Plk1 leads to mitotic arrest. Finally, the CCT-depleted cells reenter the cell cycle upon reintroduction of the purified constitutively active form of Plk1, indicating that Plk1 might be a CCT substrate.
Liu
Xiaoqi
X
Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA. liu13@fas.harvard.edu
Lin
Chin-Yo
CY
Lei
Ming
M
Yan
Shi
S
Zhou
Tianhua
T
Erikson
Raymond L
RL
D000818:Animals; D017209:Apoptosis; D064199:Cdc20 Proteins; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D010641:Phenotype; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000097869:Polo-Like Kinase 1
D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D000097869:Polo-Like Kinase 1; C533304:TCP1 protein, human; C577488:CDC20 protein, human