Inositol lipid metabolism accompanies erythroid differentiation of K562 human leukemic cells.

The role of hemin induction of K562 in inositol phospholipid metabolism has not been previously studied. K562 cells were induced to synthesize hemoglobin upon addition of bovine hemin to the culture media. The phospholipid content of K562 was determined before and after the addition of hemin. The results of this study demonstrated significant differences in the phosphoinositides between induced and non-induced cells. Phosphatidylinositol-4-phosphate (PIP) and phosphatidyl-inositol-4,5-bisphosphate (PIP2) levels increased upon induction, and remained above control levels. Phosphatidylinositol (PI) levels decreased 15 min after hemin addition, then increased to control levels by 1 h. From 2-8 h PI levels then remained depressed below control levels. These data suggest that hemoglobin induction in K562 cells occurs concomitantly with inositol phospholipid turnover.