Cell Signaling Technology

Product Pathways - Akt Signaling

Phospho-Akt (Thr308) Antibody #9275

Applications Reactivity MW (kDa) Source
W IP IF-IC F H M R Hm 60 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation  IF-IC=Immunofluorescence (Immunocytochemistry)  F=Flow Cytometry
Reactivity Key:  H=Human  M=Mouse  R=Rat  Hm=Hamster
Species enclosed in parentheses are predicted to react based on 100% sequence homology. Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

Phospho-Akt (Thr308) Antibody detects endogenous levels of Akt only when phosphorylated at Thr308. This antibody does not detect Akt phosphorylated at other sites or related kinases such as PKC and p70 S6 kinase.

Source / Purification

Polyclonal antibodies are produced by immunizing rabbits with a synthetic phospho-peptide (KLH-coupled) corresponding to residues around Thr308 of mouse Akt. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from NIH/3T3 cells, untreated or PDGF treated (100 ng/ml), using Phospho-Akt (Thr308) Antibody (upper) or Akt Antibody #9272 (lower).

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of Jurkat cells, untreated (blue) or LY294002-treated (green), using Phospho-Akt (Thr308) Antibody compared to a nonspecific negative control antibody (red).

Background

Akt, also referred to as PKB or Rac, plays a critical role in controlling survival and apoptosis (1-3). This protein kinase is activated by insulin and various growth and survival factors to function in a wortmannin-sensitive pathway involving PI3 kinase (2,3). Akt is activated by phospholipid binding and activation loop phosphorylation at Thr308 by PDK1 (4) and by phosphorylation within the carboxy terminus at Ser473. The previously elusive PDK2 responsible for phosphorylation of Akt at Ser473 has been identified as mammalian target of rapamycin (mTor) in a rapamycin-insensitive complex with rictor and Sin1 (5,6). Akt promotes cell survival by inhibiting apoptosis by phosphorylating and inactivating several targets, including Bad (7), forkhead transcription factors (8), c-Raf (9) and caspase-9. PTEN phosphatase is a major negative regulator of the PI3 kinase/Akt signaling pathway (10). LY294002 is a specific PI3 kinase inhibitor (11).Another essential Akt function is the regulation of glycogen synthesis through phosphorylation and inactivation of GSK-3α and β (12,13). Akt may also play a role in insulin stimulation of glucose transport (12).In addition to its role in survival and glycogen synthesis, Akt is involved in cell cycle regulation by preventing GSK-3β mediated phosphorylation and degradation of cyclin D1 (14) and by negatively regulating the cyclin dependent kinase inhibitors p27 Kip (15) and p21 Waf1/CIP1 (16). Akt also plays a critical role in cell growth by directly phosphorylating mTOR in a rapamycin-sensitive complex containing raptor (17). More importantly, Akt phosphorylates and inactivates tuberin (TSC2), an inhibitor of mTOR within the mTOR-raptor complex (18). Inhibition of mTOR stops the protein synthesis machinery due to inactivation of its effector, p70 S6 kinase and activation of the eukaryotic initiation factor 4E binding protein 1 (4E-EP1), an inhibitor of translation (18,19).

  1. Franke, T.F. et al. (1997) Cell 88, 435-7.
  2. Burgering, B.M. and Coffer, P.J. (1995) Nature 376, 599-602.
  3. Franke, T.F. et al. (1995) Cell 81, 727-36.
  4. Alessi, D.R. et al. (1996) EMBO J 15, 6541-51.
  5. Sarbassov, D.D. et al. (2005) Science 307, 1098-101.
  6. Jacinto, E. et al. (2006) Cell 127, 125-37.
  7. Cardone, M.H. et al. (1998) Science 282, 1318-21.
  8. Brunet, A. et al. (1999) Cell 96, 857-68.
  9. Zimmermann, S. and Moelling, K. (1999) Science 286, 1741-4.
  10. Cantley, L.C. and Neel, B.G. (1999) Proc Natl Acad Sci USA 96, 4240-5.
  11. Vlahos, C.J. et al. (1994) J Biol Chem 269, 5241-8.
  12. Hajduch, E. et al. (2001) FEBS Lett 492, 199-203.
  13. Cross, D.A. et al. (1995) Nature 378, 785-9.
  14. Diehl, J.A. et al. (1998) Genes Dev 12, 3499-511.
  15. Gesbert, F. et al. (2000) J Biol Chem 275, 39223-30.
  16. Zhou, B.P. et al. (2001) Nat Cell Biol 3, 245-52.
  17. Nave, B.T. et al. (1999) Biochem J 344 Pt 2, 427-31.
  18. Inoki, K. et al. (2002) Nat Cell Biol 4, 648-57.
  19. Manning, B.D. et al. (2002) Mol Cell 10, 151-62.

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