PMID- 12740386
OWN - NLM
STAT- MEDLINE
DCOM- 20030826
LR  - 20211203
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 278
IP  - 30
DP  - 2003 Jul 25
TI  - Mechanism of ribosomal p70S6 kinase activation by granulocyte macrophage 
      colony-stimulating factor in neutrophils: cooperation of a MEK-related, 
      THR421/SER424 kinase and a rapamycin-sensitive, m-TOR-related THR389 kinase.
PG  - 28130-8
AB  - We report here for the first time the detection of the ribosomal p70S6 kinase 
      (p70S6K) in a hematopoietic cell, the neutrophil, and the stimulation of its 
      enzymatic activity by granulocyte macrophage colony-stimulating factor (GM-CSF). 
      GM-CSF modified the Vmax of the enzyme (from 7.2 to 20.5 pmol/min/mg) and induced 
      a time- and dose-dependent phosphorylation on p70S6K residues Thr389 and 
      Thr421/Ser424. The immunosuppressant macrolide rapamycin caused either a decrease 
      in intensity of phospho-Thr389 bands in Western blots, or as a downshift in the 
      relative mobility of phospho-Thr421/Ser424 bands (consistent with the loss of 
      phosphate), but not both simultaneously. The immunosuppressant FK506 failed to 
      inhibit p70S6K activation, but was able to rescue the rapamycin-induced 
      downshift, pointing to a role for the mammalian target of rapamycin (mTOR) 
      kinase. Rapamycin also caused an inhibition (IC50 0.2 nm) of the in vitro 
      enzymatic activity of p70S6K. However, the inhibition of activity was not 
      complete, but only a 40-50%, indicating that neutrophil p70S6K activity has a 
      rapamycin-resistant component. This component was totally inhibited by 
      pre-incubating the cells with the mitogen-activated protein kinase (MAPK) kinase 
      (MEK) inhibitor PD-98059 prior to treatment with rapamycin. This indicated that a 
      kinase from the MEK/MAPK pathway also plays a role in p70S6K activation. Thus, 
      GM-CSF causes the dual activation of a rapamycin-resistant, MAPK-related kinase, 
      that targets Thr421/Ser424 S6K phosphorylation, and a rapamycin-sensitive, 
      mTOR-related kinase, that targets Thr389, both of which are needed in cooperation 
      to achieve full activation of neutrophil p70S6K.
FAU - Lehman, Jason A
AU  - Lehman JA
AD  - Department of Physiology and Biophysics, Wright State University School of 
      Medicine, Dayton, Ohio 45435, USA.
FAU - Calvo, Victor
AU  - Calvo V
FAU - Gomez-Cambronero, Julian
AU  - Gomez-Cambronero J
LA  - eng
GR  - HL056653/HL/NHLBI 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.
DEP - 20030511
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (Flavonoids)
RN  - 0 (Immunosuppressive Agents)
RN  - 2ZD004190S (Threonine)
RN  - 83869-56-1 (Granulocyte-Macrophage Colony-Stimulating Factor)
RN  - EC 2.7.- (Protein Kinases)
RN  - EC 2.7.1.1 (mTOR protein, mouse)
RN  - EC 2.7.11.1 (Ribosomal Protein S6 Kinases, 70-kDa)
RN  - EC 2.7.11.1 (TOR Serine-Threonine Kinases)
RN  - EC 3.1.3.1 (Alkaline Phosphatase)
RN  - SJE1IO5E3I (2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one)
RN  - W36ZG6FT64 (Sirolimus)
SB  - IM
MH  - 3T3 Cells
MH  - Alkaline Phosphatase/metabolism
MH  - Animals
MH  - Blotting, Western
MH  - Dose-Response Relationship, Drug
MH  - Enzyme Activation
MH  - Enzyme Inhibitors/pharmacology
MH  - Flavonoids/pharmacology
MH  - Granulocyte-Macrophage Colony-Stimulating Factor/*metabolism
MH  - Immunosuppressive Agents/pharmacology
MH  - Inhibitory Concentration 50
MH  - Kinetics
MH  - MAP Kinase Signaling System
MH  - Mice
MH  - Models, Biological
MH  - Neutrophils/*enzymology/metabolism
MH  - Phosphorylation
MH  - Precipitin Tests
MH  - Protein Kinases/*metabolism
MH  - Ribosomal Protein S6 Kinases, 70-kDa/*metabolism
MH  - Ribosomes/*enzymology
MH  - Sirolimus/pharmacology
MH  - TOR Serine-Threonine Kinases
MH  - Threonine/chemistry
MH  - Time Factors
EDAT- 2003/05/13 05:00
MHDA- 2003/08/27 05:00
CRDT- 2003/05/13 05:00
PHST- 2003/05/13 05:00 [pubmed]
PHST- 2003/08/27 05:00 [medline]
PHST- 2003/05/13 05:00 [entrez]
AID - S0021-9258(20)84544-X [pii]
AID - 10.1074/jbc.M300376200 [doi]
PST - ppublish
SO  - J Biol Chem. 2003 Jul 25;278(30):28130-8. doi: 10.1074/jbc.M300376200. Epub 2003 
      May 11.