Anti-p70 S6 Kinase

p70 S6 kinase is a mitogen-activated Ser/Thr protein kinase that is required for cell growth and G1 cell cycle progression (1). 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 N-terminus that encode a nuclear localizing signal (1). Both isoforms lie on a mitogen-activated signaling pathway downstream of phosphoinositide 3 kinase (PI3K) and the target of rapamycin FRAP/mTOR, and 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 (2). Prior phosphorylation of Thr389 is required for the action of phosphoinositide 3- dependent protein kinase 1 (PDK1) on Thr229 (3,4). 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) (1,5,6). 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). Applications: Suitable for use in ELISA, Western Blot and Immunoprecipitation. Other applications not tested. Recommended Dilution: Western Blot: 1:1000, Incubate membrane with diluted antibody in 5% BSA, 1X TBS, 0.1% Tween-20 at 4°C with gentle shaking, overnight., Immunoprecipitation: 1:50, 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.