[Enhancement of membrane phospholipid breakdown and synthesis during phagocytosis in cultured chick retinal pigment epithelial cells].
In chick cultured retinal pigment epithelial cells (RPE cells) phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are major membrane phospholipid constituents. The synthesis of these phospholipids occurred gradually, compared to rapid synthesis of phosphatidic acid (PA) and phosphatidylinositol (PI). Exposure of RPE cells to latex particles elicited active phagocytosis. In [3H] glycerol- or [3H] arachidonic acid-prelabeled cells, a transient decrease in PI was observed without increases in the level of either diacylglycerol (DG) or PA. However, the radioactivity of PC and PE significantly increased. The enhancement of de novo synthesis of phospholipids, measured by the incorporation of [3H] glycerol, was not stimulated within 2 hours after the addition of latex particles. The transient increase in the ratio of [14C] choline/[3H] glycerol in PC may indicate the accelerated synthesis of PC but not via a de novo synthetic pathway. The results obtained in the present study indicate that DG, produced by PI breakdown, may be utilized in PC synthesis for the replenishment of membrane lost during phagocytosis.
Nakashima
S
S
Tsunematsu
Y
Y
Nozawa
Y
Y
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002642:Chick Embryo; D008563:Membrane Lipids / Q000096:biosynthesis / Q000378:metabolism*; D010587:Phagocytosis; D010713:Phosphatidylcholines / Q000096:biosynthesis / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000096:biosynthesis / Q000378:metabolism; D010743:Phospholipids / Q000096:biosynthesis / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism*
D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010743:Phospholipids