Interaction of phosphatidylinositol-4-monophosphate with a low activity form of DNA polymerase alpha: a potential mechanism for enzyme activation.
1. DNA polymerase alpha isolated from Norman murine myxosarcoma exhibited two isozyme forms, one with low specific activity and low DNA binding affinity (A1), and one with high specific activity and high DNA binding affinity (A2). 2. DNA polymerase alpha A1, but not A2, showed a significant increase in specific activity after treatment with phosphatidylinositol, ATP and phosphatidylinositol kinase, or with phosphatidylinositol-4-monophosphate. 3. Treatment of DNA polymerase alpha A1 with the phospholipase C hydrolysis product of phosphatidylinositol-4-monophosphate, inositol-1,4-bisphosphate, was sufficient to effect the transient increase in activity of polymerase A1 to a form not chromatographically distinguishable from isozyme form A2.
Sylvia
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VL
Department of Anatomy, College of Veterinary Medicine, Texas A & M University, College Station 77843.
Joe
C O
CO
Norman
J O
JO
Curtin
G M
GM
Tilley
R D
RD
Busbee
D L
DL
D000818:Animals; D004247:DNA / Q000378:metabolism; D004257:DNA Polymerase II / Q000378:metabolism*; D019915:DNA Primase; D004789:Enzyme Activation / Q000187:drug effects; D007295:Inositol Phosphates / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000494:pharmacology*; D012316:RNA Nucleotidyltransferases / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D007295:Inositol Phosphates; D007527:Isoenzymes; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C037178:phosphatidylinositol 4-phosphate; C044259:inositol 1,4-bis(phosphate); D004247:DNA; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases; D004257:DNA Polymerase II