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Gene Review

PIK3R2  -  phosphoinositide-3-kinase, regulatory...

Homo sapiens

Synonyms: MPPH, MPPH1, P85B, PI3-kinase regulatory subunit beta, PI3-kinase subunit p85-beta, ...
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Disease relevance of PIK3R2

  • Expression and characterization of the p85 subunit of the phosphatidylinositol 3-kinase complex and a related p85 beta protein by using the baculovirus expression system [1].

High impact information on PIK3R2

  • Amino acid sequence analysis and cDNA cloning reveals two related 85 kd proteins (p85 alpha and p85 beta), which both contain one SH3 and two SH2 regions (src homology regions) [2].
  • While not detectable in 3T3-L1 adipocytes, the p85 beta isoform was also found to associate with IRS-1 in response to insulin receptor activation in COS-1 and CHO-T cells [3].
  • In contrast, stimulation of the TCR/CD3 complex or PKC, results in a marked and rapid increase in phosphorylation of p85 beta on threonine residues [4].
  • The presence of the p85 beta locus coincided with the presence of chromosome 19 [5].
  • Specific antisera detect p85 alpha, but not p85 beta, associated with PtdIns 3-kinase activity in various cell types [1].

Biological context of PIK3R2


Anatomical context of PIK3R2


Other interactions of PIK3R2


Analytical, diagnostic and therapeutic context of PIK3R2

  • However, selective immunoprecipitation of p85 beta from unstimulated COS-1 or CHO-T cell lysates was accompanied by higher levels of PI 3-kinase activity than that associated with p85 alpha [3].
  • Western blot analysis of cardiomyocyte lysates revealed expression of p85 alpha and p85 beta but no detectable amounts of the splice variants of p85 alpha [6].


  1. Expression and characterization of the p85 subunit of the phosphatidylinositol 3-kinase complex and a related p85 beta protein by using the baculovirus expression system. Gout, I., Dhand, R., Panayotou, G., Fry, M.J., Hiles, I., Otsu, M., Waterfield, M.D. Biochem. J. (1992) [Pubmed]
  2. Characterization of two 85 kd proteins that associate with receptor tyrosine kinases, middle-T/pp60c-src complexes, and PI3-kinase. Otsu, M., Hiles, I., Gout, I., Fry, M.J., Ruiz-Larrea, F., Panayotou, G., Thompson, A., Dhand, R., Hsuan, J., Totty, N. Cell (1991) [Pubmed]
  3. Regulation by insulin of phosphatidylinositol 3'-kinase bound to alpha- and beta-isoforms of p85 regulatory subunit. Baltensperger, K., Kozma, L.M., Jaspers, S.R., Czech, M.P. J. Biol. Chem. (1994) [Pubmed]
  4. Divergent regulation of phosphatidylinositol 3-kinase P85 alpha and P85 beta isoforms upon T cell activation. Reif, K., Gout, I., Waterfield, M.D., Cantrell, D.A. J. Biol. Chem. (1993) [Pubmed]
  5. Chromosomal localization of human p85 alpha, a subunit of phosphatidylinositol 3-kinase, and its homologue p85 beta. Volinia, S., Patracchini, P., Otsu, M., Hiles, I., Gout, I., Calzolari, E., Bernardi, F., Rooke, L., Waterfield, M.D. Oncogene (1992) [Pubmed]
  6. Diversification of cardiac insulin signaling involves the p85 alpha/beta subunits of phosphatidylinositol 3-kinase. Kessler, A., Uphues, I., Ouwens, D.M., Till, M., Eckel, J. Am. J. Physiol. Endocrinol. Metab. (2001) [Pubmed]
  7. Insulin-like growth factor-I stimulates Shc-dependent phosphatidylinositol 3-kinase activation via Grb2-associated p85 in vascular smooth muscle cells. Radhakrishnan, Y., Maile, L.A., Ling, Y., Graves, L.M., Clemmons, D.R. J. Biol. Chem. (2008) [Pubmed]
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