PMID- 10567431
OWN - NLM
STAT- MEDLINE
DCOM- 19991229
LR  - 20211203
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 274
IP  - 48
DP  - 1999 Nov 26
TI  - Immunopurified mammalian target of rapamycin phosphorylates and activates p70 S6 
      kinase alpha in vitro.
PG  - 34493-8
AB  - p70 S6 kinase alpha (p70alpha) is activated in vivo through a multisite 
      phosphorylation in response to mitogens if a sufficient supply of amino acids is 
      available or to high concentrations of amino acids per se. The immunosuppressant 
      drug rapamycin inhibits p70alpha activation in a manner that can be overcome by 
      coexpression of p70alpha with a rapamycin-resistant mutant of the mammalian 
      target of rapamycin (mTOR) but only if the mTOR kinase domain is intact. We 
      report here that a mammalian recombinant p70alpha polypeptide, extracted in an 
      inactive form from rapamycin-treated cells, can be directly phosphorylated by the 
      mTOR kinase in vitro predominantly at the rapamycin-sensitive site Thr-412. 
      mTOR-catalyzed p70alpha phosphorylation in vitro is accompanied by a substantial 
      restoration in p70alpha kinase activity toward its physiologic substrate, the 40 
      S ribosomal protein S6. Moreover, sequential phosphorylation of p70alpha by mTOR 
      and 3-phosphoinositide-dependent protein kinase 1 in vitro resulted in a 
      synergistic stimulation of p70alpha activity to levels similar to that attained 
      by serum stimulation in vivo. These results indicate that mTOR is likely to 
      function as a direct activator of p70 in vivo, although the relative contribution 
      of mTOR-catalyzed p70 phosphorylation in each of the many circumstances that 
      engender p70 activation remains to be defined.
FAU - Isotani, S
AU  - Isotani S
AD  - Biosignal Research Center, Kobe University, Kobe 657-8501, Japan.
FAU - Hara, K
AU  - Hara K
FAU - Tokunaga, C
AU  - Tokunaga C
FAU - Inoue, H
AU  - Inoue H
FAU - Avruch, J
AU  - Avruch J
FAU - Yonezawa, K
AU  - Yonezawa K
LA  - eng
GR  - CA73818/CA/NCI NIH HHS/United States
GR  - DK17776/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Culture Media, Serum-Free)
RN  - 0 (Mitogens)
RN  - 0 (Recombinant Fusion Proteins)
RN  - EC 2.7.- (Protein Kinases)
RN  - EC 2.7.1.- (Phosphotransferases (Alcohol Group Acceptor))
RN  - EC 2.7.1.1 (MTOR protein, human)
RN  - EC 2.7.11.1 (3-Phosphoinositide-Dependent Protein Kinases)
RN  - EC 2.7.11.1 (PDPK1 protein, human)
RN  - EC 2.7.11.1 (Protein Serine-Threonine Kinases)
RN  - EC 2.7.11.1 (Ribosomal Protein S6 Kinases)
RN  - EC 2.7.11.1 (TOR Serine-Threonine Kinases)
SB  - IM
MH  - 3-Phosphoinositide-Dependent Protein Kinases
MH  - Cell Line
MH  - Culture Media, Serum-Free/pharmacology
MH  - Enzyme Activation/drug effects
MH  - Humans
MH  - Immunoblotting
MH  - Mitogens/pharmacology
MH  - Mutation
MH  - Phosphorylation/drug effects
MH  - Phosphotransferases (Alcohol Group Acceptor)/genetics/isolation & 
      purification/*metabolism
MH  - Precipitin Tests
MH  - *Protein Kinases
MH  - Protein Serine-Threonine Kinases/genetics/metabolism
MH  - Recombinant Fusion Proteins/genetics/isolation & purification/metabolism
MH  - Ribosomal Protein S6 Kinases/genetics/*metabolism
MH  - TOR Serine-Threonine Kinases
EDAT- 1999/11/24 00:00
MHDA- 1999/11/24 00:01
CRDT- 1999/11/24 00:00
PHST- 1999/11/24 00:00 [pubmed]
PHST- 1999/11/24 00:01 [medline]
PHST- 1999/11/24 00:00 [entrez]
AID - S0021-9258(19)53558-X [pii]
AID - 10.1074/jbc.274.48.34493 [doi]
PST - ppublish
SO  - J Biol Chem. 1999 Nov 26;274(48):34493-8. doi: 10.1074/jbc.274.48.34493.