title: The yeast Tor signaling pathway is involved in G2/M transition via polo-kinase.
abstract: 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.
authors.affiliation: Biosignal Research Center, Kobe University, Kobe, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Nakashima
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Maruki
authors.forename: Yuko
authors.initials: Y
authors.lastname: Imamura
authors.forename: Chika
authors.initials: C
authors.lastname: Kondo
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kawamata
authors.forename: Ippei
authors.initials: I
authors.lastname: Kawanishi
authors.forename: Hideki
authors.initials: H
authors.lastname: Takata
authors.forename: Akira
authors.initials: A
authors.lastname: Matsuura
authors.forename: Kyung S
authors.initials: KS
authors.lastname: Lee
authors.forename: Ushio
authors.initials: U
authors.lastname: Kikkawa
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ohsumi
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Yonezawa
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kamada
mesh_terms: 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
chemical_list: 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