phosphatidylinositol 3 kinase catalytic subunit alpha (PIK3CA)

Function

• phosphorylates Ptdins, Ptdins4P & Ptdins(4,5)P2 with a preference for Ptdins(4,5)P2
• heterodimer of a p110 (catalytic) & a p85 (regulatory) subunit
• binds to IRS1 in nuclear extracts
• interacts with RUFY3

ATP + 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate
                    <-->
ADP + 1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate

Structure

• belongs to the PI3/PI4-kinase family
• contains 1 C2 domain
• contains 1 PI3K/PI4K domain

Pathology

• defects in PIK3CA are associated:
  • colorectal cancer
  • breast cancer
  • epithelial ovarian cancer
• PIK3CA mutations also associated with
  • PIK3CA overgrowth syndrome
  • Klippel-Trenaunay-Weber syndrome

Laboratory

• PIK3CA gene in cancer

More general terms

• PI-3-kinase p110

Database

• UniProt: http://www.uniprot.org/uniprot/P42336.html
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:5290
• OMIM: https://mirror.omim.org/entry/114480
• OMIM: https://mirror.omim.org/entry/114500
• OMIM: https://mirror.omim.org/entry/171834
• OMIM: https://mirror.omim.org/entry/604370
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=5290