The yeast Tor signaling pathway is involved in G2/M transition via polo-kinase.
The target of rapamycin (Tor) protein plays central roles in cell growth. Rapamycin inhibits cell growth and promotes cell cycle arrest at G1 (G0). However, little is known about whether Tor is involved in other stages of the cell division cycle. Here we report that the rapamycin-sensitive Tor complex 1 (TORC1) is involved in G2/M transition in S. cerevisiae. Strains carrying a temperature-sensitive allele of KOG1 (kog1-105) encoding an essential component of TORC1, as well as yeast cell treated with rapamycin show mitotic delay with prolonged G2. Overexpression of Cdc5, the yeast polo-like kinase, rescues the growth defect of kog1-105, and in turn, Cdc5 activity is attenuated in kog1-105 cells. The TORC1-Type2A phosphatase pathway mediates nucleocytoplasmic transport of Cdc5, which is prerequisite for its proper localization and function. The C-terminal polo-box domain of Cdc5 has an inhibitory role in nuclear translocation. Taken together, our results indicate a novel function of Tor in the regulation of cell cycle and proliferation.
Nakashima
Akio
A
Biosignal Research Center, Kobe University, Kobe, Japan.
Maruki
Yoshiko
Y
Imamura
Yuko
Y
Kondo
Chika
C
Kawamata
Tomoko
T
Kawanishi
Ippei
I
Takata
Hideki
H
Matsuura
Akira
A
Lee
Kyung S
KS
Kikkawa
Ushio
U
Ohsumi
Yoshinori
Y
Yonezawa
Kazuyoshi
K
Kamada
Yoshiaki
Y
D000483:Alleles; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002455:Cell Division; D016195:G2 Phase; D008565:Membrane Proteins / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
D018797:Cell Cycle Proteins; C515118:Kog1 protein, S cerevisiae; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C500749:target of rapamycin protein, S cerevisiae; C081927:CDC5 protein, S cerevisiae