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Product Includes Quantity Applications Reactivity MW(kDa) Isotype
Phospho-p70 S6 Kinase (Thr389) (108D2) Rabbit mAb 9234 100 µl
H M R Mk 70, 85 Rabbit IgG
p70 S6 Kinase (49D7) Rabbit mAb 2708 100 µl
H M R Mk 70, 85 Rabbit 

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Product Description

PhosphoPlus® Duets from Cell Signaling Technology (CST) provide a means to assess protein activation status. Each Duet contains an activation-state and total protein antibody to your target of interest. These antibodies have been selected from CST's product offering based upon superior performance in specified applications.


p70 S6 kinase is a mitogen activated Ser/Thr protein kinase that is required for cell growth and G1 cell cycle progression (1,2). p70 S6 kinase phosphorylates the S6 protein of the 40S ribosomal subunit and is involved in translational control of 5' oligopyrimidine tract mRNAs (1). A second isoform, p85 S6 kinase, is derived from the same gene and is identical to p70 S6 kinase except for 23 extra residues at the amino terminus, which encode a nuclear localizing signal (1). Both isoforms lie on a mitogen activated signaling pathway downstream of phosphoinositide-3 kinase (PI-3K) and the target of rapamycin, FRAP/mTOR, a pathway distinct from the Ras/MAP kinase cascade (1). The activity of p70 S6 kinase is controlled by multiple phosphorylation events located within the catalytic, linker and pseudosubstrate domains (1). Phosphorylation of Thr229 in the catalytic domain and Thr389 in the linker domain are most critical for kinase function (1). Phosphorylation of Thr389, however, most closely correlates with p70 kinase activity in vivo (3). Prior phosphorylation of Thr389 is required for the action of phosphoinositide 3-dependent protein kinase 1 (PDK1) on Thr229 (4,5). Phosphorylation of this site is stimulated by growth factors such as insulin, EGF and FGF, as well as by serum and some G-protein-coupled receptor ligands, and is blocked by wortmannin, LY294002 (PI-3K inhibitor) and rapamycin (FRAP/mTOR inhibitor) (1,6,7). Ser411, Thr421 and Ser424 lie within a Ser-Pro-rich region located in the pseudosubstrate region (1). Phosphorylation at these sites is thought to activate p70 S6 kinase via relief of pseudosubstrate suppression (1,2). Another LY294002 and rapamycin sensitive phosphorylation site, Ser371, is an in vitro substrate for mTOR and correlates well with the activity of a partially rapamycin resistant mutant p70 S6 kinase (8).


1.  Saitoh M et al. (2002) J Biol Chem 277, 20104–12

2.  Pullen, N. and Thomas, G. (1997) FEBS Lett 410, 78-82.

3.  Dufner, A. and Thomas, G. (1999) Exp Cell Res 253, 100-9.

4.  Weng, Q.P. et al. (1998) J Biol Chem 273, 16621-9.

5.  Pullen, N. et al. (1998) Science 279, 707-10.

6.  Alessi, D.R. et al. (1998) Curr Biol 8, 69-81.

7.  Polakiewicz, R.D. et al. (1998) J Biol Chem 273, 23534-41.

8.  Fingar, D.C. et al. (2002) Genes Dev 16, 1472-87.


Entrez-Gene Id 6198
Swiss-Prot Acc. P23443


For Research Use Only. Not For Use In Diagnostic Procedures.
Cell Signaling Technology® is a trademark of Cell Signaling Technology, Inc.
PhosphoPlus® is a trademark of Cell Signaling Technology, Inc.
U.S. Patent No. 5,675,063.