Characterization of the bovine brain cytosolic phosphatidylinositol 3-kinase complex.
Receptor-linked phosphatidylinositol (PtdIns) 3-kinase may generate a second-messenger signal. Here a large-scale purification of the bovine brain enzyme, based on methods developed by Morgan, Smith and Parker [(1990) Eur. J. Biochem. 191, 761-767] and Fry, Panayotou, Dhand, Ruiz-Larrea, Gout, Nguyen, Courtneidge and Waterfield [(1992) Biochem. J. 288, 383-393] is described. The purified enzyme is shown to be a heterodimer of 85 kDa and 110 kDa protein subunits (p85 and p110). Labelling with 5'-p-fluorosulphonylbenzoyladenosine shows that p110 contains an ATP-binding site and confers catalytic activity to the complex. The purified complex is known to be highly phosphorylated on both p85 alpha and p110 subunits, and dephosphorylation generates a deactivated complex, indicating that phosphorylation is an important covalent modification of the complex and may modulate PtdIns 3-kinase activity.
Ludwig Institute for Cancer Research, London, U.K.
F
F
Ruiz-Larrea
P
P
Vicendo
P
P
Yaish
P
P
End
G
G
Panayotou
M J
MJ
Fry
S J
SJ
Morgan
A
A
Thompson
P J
PJ
Parker
M D
MD
Waterfield
D000241:Adenosine / Q000031:analogs & derivatives; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology*; D002384:Catalysis; D002417:Cattle; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D019869:Phosphatidylinositol 3-Kinases; D010766:Phosphorylation; D010770:Phosphotransferases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism
C010959:5'-(4-fluorosulfonylbenzoyl)adenosine; D000255:Adenosine Triphosphate; D010770:Phosphotransferases; D019869:Phosphatidylinositol 3-Kinases; D017479:Receptors, Platelet-Derived Growth Factor; D000241:Adenosine