PMID- 10518537
OWN - NLM
STAT- MEDLINE
DCOM- 19991124
LR  - 20201209
IS  - 0027-8424 (Print)
IS  - 0027-8424 (Linking)
VI  - 96
IP  - 21
DP  - 1999 Oct 12
TI  - Regulation of nuclear translocation of forkhead transcription factor AFX by
      protein kinase B.
PG  - 11836-41
AB  - The regulation of intracellular localization of AFX, a human Forkhead
      transcription factor, was studied. AFX was recovered as a phosphoprotein from
      transfected COS-7 cells growing in the presence of FBS, and the phosphorylation
      was eliminated by wortmannin, a potent inhibitor of phosphatidylinositol (PI)
      3-kinase. AFX was phosphorylated in vitro by protein kinase B (PKB), a downstream
      target of PI 3-kinase, but a mutant protein in which three putative
      phosphorylation sites of PKB had been replaced by Ala was not recognized by PKB. 
      In Chinese hamster ovary cells (CHO-K1) cultured with serum, the AFX protein
      fused with green fluorescence protein (AFX-GFP) is localized mainly in the
      cytoplasm, and wortmannin induced transient nuclear translocation of the fusion
      protein. The AFX-GFP mutant in which all three phosphorylation sites had been
      replaced by Ala was detected exclusively in the cell nucleus. AFX-GFP was in the 
      nucleus when the cells were infected with an adenovirus vector encoding a
      dominant-negative form of either PI 3-kinase or PKB, whereas the fusion protein
      stayed in the cytoplasm when the cells expressed constitutively active PKB. In
      CHO-K1 cells expressing AFX-GFP, DNA fragmentation was induced by the stable PI
      3-kinase inhibitor LY294002, and the expression of the active form of PKB
      suppressed this DNA fragmentation. The phosphorylation site mutant of AFX-GFP
      enhanced DNA fragmentation irrespective of the presence and absence of PI
      3-kinase inhibitor. These results indicate that the nuclear translocation of AFX 
      is negatively regulated through its phosphorylation by PKB.
FAU - Takaishi, H
AU  - Takaishi H
AD  - Biosignal Research Center, Faculty of Science, Kobe University, Kobe 657-8501,
      Japan.
FAU - Konishi, H
AU  - Konishi H
FAU - Matsuzaki, H
AU  - Matsuzaki H
FAU - Ono, Y
AU  - Ono Y
FAU - Shirai, Y
AU  - Shirai Y
FAU - Saito, N
AU  - Saito N
FAU - Kitamura, T
AU  - Kitamura T
FAU - Ogawa, W
AU  - Ogawa W
FAU - Kasuga, M
AU  - Kasuga M
FAU - Kikkawa, U
AU  - Kikkawa U
FAU - Nishizuka, Y
AU  - Nishizuka Y
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Blood Proteins)
RN  - 0 (Cell Cycle Proteins)
RN  - 0 (DNA, Complementary)
RN  - 0 (FOXO4 protein, human)
RN  - 0 (Forkhead Transcription Factors)
RN  - 0 (Proto-Oncogene Proteins)
RN  - 0 (Transcription Factors)
RN  - EC 2.7.11.1 (Protein-Serine-Threonine Kinases)
RN  - EC 2.7.11.1 (Proto-Oncogene Proteins c-akt)
SB  - IM
MH  - Animals
MH  - Blood Proteins/*metabolism
MH  - Brain/metabolism
MH  - CHO Cells
MH  - Cell Cycle Proteins
MH  - Cricetinae
MH  - DNA Fragmentation
MH  - DNA, Complementary/metabolism
MH  - Flow Cytometry
MH  - Forkhead Transcription Factors
MH  - Gene Library
MH  - Humans
MH  - Immunoblotting
MH  - Models, Genetic
MH  - Mutagenesis
MH  - Phosphatidylinositol 3-Kinases/metabolism
MH  - Phosphorylation
MH  - Precipitin Tests
MH  - *Protein-Serine-Threonine Kinases
MH  - Proto-Oncogene Proteins/*metabolism
MH  - Proto-Oncogene Proteins c-akt
MH  - Time Factors
MH  - *Transcription Factors
MH  - Transcription, Genetic
PMC - PMC18373
EDAT- 1999/10/16 00:00
MHDA- 1999/10/16 00:01
CRDT- 1999/10/16 00:00
PHST- 1999/10/16 00:00 [pubmed]
PHST- 1999/10/16 00:01 [medline]
PHST- 1999/10/16 00:00 [entrez]
AID - 10.1073/pnas.96.21.11836 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 1999 Oct 12;96(21):11836-41. doi:
      10.1073/pnas.96.21.11836.