Phosphatidylinositol 3-kinase: Structure and expression of the 110 kd catalytic subunit

Ian D. Hiles, Masayuki Otsu, Stefano Volinia, Michael J. Fry, Ivan Gout, Ritu Dhand, George Panayotou, Fernanda Ruiz-Larrea, Andrew Thompson, Nicholas F. Totty, J. Justin Hsuan, Sara A. Courtneidge, Peter J. Parker, Michael D. Waterfield

Research output: Contribution to journalArticlepeer-review

608 Scopus citations


Purified bovine brain phosphatidylinositol 3-kinase (PI3-kinase) is composed of 85 kd and 110 kd subunits. The 85 kd subunit (p85α) lacks PI3-kinase activity and acts as an adaptor, coupling the 110 kd subunit (p110) to activated protein tyrosine kinases. Here the characterization of the p110 subunit is presented. cDNA cloning reveals p110 to be a 1068 aa protein related to Vps34p, a S. cerevisiae protein involved in the sorting of proteins to the vacuole. p110 expressed in insect cells possesses PI3-kinase activity and associates with p85α into an active p85α-p110 complex that binds the activated colony-stimulating factor 1 receptor. p110 expressed in COS-1 cells is catalytically active only when complexed with p85α.

Original languageEnglish (US)
Pages (from-to)419-429
Number of pages11
Issue number3
StatePublished - Aug 7 1992
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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