Cell Signaling Technology

Product Pathways - PI3K / Akt Signaling

Phospho-PI3 Kinase p85 (Tyr458)/p55 (Tyr199) Antibody #4228

Applications Reactivity Sensitivity MW (kDa) Source
W IP M (H) (R) (Mk) (B) Endogenous 60 and 85 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey  B=Bovine
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-PI3 Kinase p85 (Tyr458)/p55 (Tyr199) Antibody detects endogenous levels of p85/p55 only when phosphorylated at Tyr458/Tyr199.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Tyr458 of mouse p85. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from NIH/3T3-Src cells, untreated or treated with lambda phosphatase and from C2C12 cells, untreated or treated with H2O2, using Phospho-PI3 Kinase p85 (Tyr458)/p55 (Tyr199) Antibody.

Background

Phosphoinositide 3-kinase (PI3K) catalyzes the production of phosphatidylinositol-3,4,5-triphosphate by phosphorylating phosphatidylinositol (PI), phosphatidylinositol-4-phosphate (PIP), and phosphatidylinositol-4,5-bisphosphate (PIP2). Growth factors and hormones trigger this phosphorylation event, which in turn coordinates cell growth, cell cycle entry, cell migration, and cell survival (1). PTEN reverses this process, and research studies have shown that the PI3K signaling pathway is constitutively activated in human cancers that have loss of function of PTEN (2). PI3Ks are composed of a catalytic subunit (p110) and a regulatory subunit. Various isoforms of the catalytic subunit (p110α, p110β, p110γ, and p110δ) have been isolated, and the regulatory subunits that associate with p110α, p110β, and p110δ are p85α and p85β (3). In contrast, p110γ associates with a p101 regulatory subunit that is unrelated to p85. Furthermore, p110γ is activated by βγ subunits of heterotrimeric G proteins (4).

Protein extracts from 3T3-Src cells were profiled by PhosphoScan® to identify phosphotyrosine peptides. Tyr458 of PI3K p85 and Tyr199 of PI3K p55 were among 180 phosphopeptides and 185 phosphotyrosine sites identified (5).

  1. Cantley, L.C. (2002) Science 296, 1655-7.
  2. Simpson, L. and Parsons, R. (2001) Exp Cell Res 264, 29-41.
  3. Neri, L.M. et al. (2002) Biochim Biophys Acta 1584, 73-80.
  4. Stoyanov, B. et al. (1995) Science 269, 690-3.
  5. Rush, J. et al. (2005) Nat. Biotechnol. 23, 94-101.

Application References

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Companion Products

US Patent No. 7,939,636 and foreign equivalents assigned to Cell Signaling Technology, Inc.

For Research Use Only. Not For Use In Diagnostic Procedures.

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