Rapid changes in phospholipid metabolism in the nuclei of Swiss 3T3 cells induced by treatment of the cells with insulin-like growth factor I.
When highly-purified nuclei of Swiss-mouse 3T3 cells are incubated with [32P]-gamma ATP, radioactivity is incorporated into phosphatidic acid and the two polyphosphoinositol lipids, phosphatidylinositol(4)P and phosphatidylinositol(4,5)P2. If the cells are pre-treated with insulin-like growth factor I, this incorporation into the phospholipids is decreased. The effect is maximal by 2 minutes, is transient in that it has disappeared by one hour, and is increased markedly by the co-addition of bombesin, even though bombesin alone has no effect. We suggest that some aspect of polyphosphoinositide metabolism is altered in the nucleus (leading to a decreased radiolabelling) when the cells are treated with mitogenic growth factors, and that this change in inositide metabolism is a very early event in the sequence leading to cell division.
Cocco
L
L
Istituto di Morfologia Umana Normale, University of Chieti, Italy.
Martelli
A M
AM
Gilmour
R S
RS
Ognibene
A
A
Manzoli
F A
FA
Irvine
R F
RF
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001839:Bombesin / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002478:Cells, Cultured; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D008854:Microscopy, Electron; D010712:Phosphatidic Acids / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D010766:Phosphorylation; D013002:Somatomedins / Q000494:pharmacology*
D010712:Phosphatidic Acids; D010716:Phosphatidylinositols; D010743:Phospholipids; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D000255:Adenosine Triphosphate; D001839:Bombesin