title: Identification of four novel human phosphoinositide 3-kinases defines a multi-isoform subfamily.
abstract: Phosphoinositide (PI) 3-kinases have critical roles in diverse cellular signalling processes and in protein trafficking. This suggests that like other intracellular signalling molecules, e.g., phospholipase C and protein kinase C, there might be a large family of PI 3-kinase isoforms with the individual members having discrete signalling roles. Reverse transcription-polymerase chain reaction methods, using degenerate oligonucleotide primers against the lipid kinase consensus region, revealed eight sequences from human cDNA containing a high degree of identity to the family of PI 3-kinases. The sequences obtained included the previously described p110 alpha, p110 beta, and p110 gamma isoforms and HsVps34. Additionally, we have identified four novel sequences which are related to PI 3-kinases. Three of the novel sequences would appear to form a distinct sub-family of PI 3-kinases. We report the expression of these novel PI 3-kinases in human tissues and in cells derived from normal breast.
authors.affiliation: Section of Cell Biology and Experimental Pathology, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom.
authors.forename: L K
authors.initials: LK
authors.lastname: Ho
authors.forename: D
authors.initials: D
authors.lastname: Liu
authors.forename: M
authors.initials: M
authors.lastname: Rozycka
authors.forename: R A
authors.initials: RA
authors.lastname: Brown
authors.forename: M J
authors.initials: MJ
authors.lastname: Fry
mesh_terms: D015152:Blotting, Northern; D001940:Breast / Q000201:enzymology*; D003001:Cloning, Molecular; D017931:DNA Primers; D016208:Databases, Factual; D015870:Gene Expression; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry* / Q000235:genetics; D008198:Lymph Nodes / Q000201:enzymology; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D007527:Isoenzymes; D012333:RNA, Messenger; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor)