Effect of staurosporine on the induction of actin/gelsolin in PMA-treated HL-60 cells.

Staurosporine, an inhibitor of protein kinase C (PKC), has been shown to inhibit the induction of two cytosolic proteins, p42 and p91, during the differentiation of HL-60 cells initiated by PMA treatment. Differentiation of these cells into macrophages was also blocked. p42 has been identified as actin by Western Blot analysis and previous studies have demonstrated p91 to be the Ca+(+)-dependent actin-binding protein gelsolin. Increased levels of these proteins may be important for the attainment of macrophage functions, e.g. phagocytosis and secretion. These studies may therefore establish a link between PKC activation and the induction of specific cellular proteins, such as actin and gelsolin, as important monocyte maturation products without which the cells will be restricted from acquiring certain macrophage activities.