Anti-phospho-p70 S6 Kinase (Ser371)

p70 S6 kinase phosphorylates the S6 protein of the 40S ribosomal subunit and is involved in translational control of 5' oligopyrimidine tract mRNAs. A second isoform, p85 S6 kinase, is identical to p70 S6 kinase except for 23 extra residues at the amino- terminus that encode a nuclear localizing signal. Both isoforms lie on a mitogen-activated signaling pathway downstream of phosphoinositide 3 kinase (PI3K). Phosphorylation of Thr229 in the catalytic domain and Thr389 in the linker domain are most critical for kinase function. Phosphorylation of Thr389, however, most closely correlates with p70 kinase activity in vivo. Prior phosphorylation of Thr389 is required for the action of phosphoinositide 3-dependent protein kinase 1 (PDK1) on Thr229. 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 (PI3 kinase inhibitor) and rapamycin (FRAP/mTOR inhibitor). Ser411, Thr421 and Ser424 lie within a Ser-Pro-rich region located in the pseudosubstrate region. Phosphorylation at these sites is thought to activate p70 S6 kinase via relief of pseudosubstrate suppression. Another LY294002 and rapamycin sensitive phosphorylation site, Ser371, has been shown to be an in vitro substrate for mTOR and correlates well with the activity of a partially rapamycin resistant mutant p70 S6 kinase. Applications: Suitable for use in Western Blot. Other applications have not been tested. Recommended Dilution: Western Blot: 1:1000 Incubate membrane with diluted antibody in 5% BSA, 1xTBS, 0.1% Tween-20 overnight at 4ºC with gentle shaking., Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4°C for short-term only. For long-term storage, store at -20°C. Aliquots are stable for at least 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.