Expression of glycosylphosphatidylinositol-anchored NAD glycohydrolase in differentiated HL60 cells by phorbol ester

Human leukemic HL60 cells are known to express NAD glycohydrolase (NADase) activity following differentiation into macrophage-like cells by 12-O-tetradecanoylphorbol-13-acetate (TPA) or granulocyte-like cells by retinoic acid (RA) treatment. Recently, it was reported that 46 kDa human leukocyte antigen, CD38, expressed by RA-differentiated HL60 cells contained NADase, ADP-ribosyl cyclase and cyclic ADP-ribose hydrolase activities. In the present study we questioned whether the NADase activity found in TPA-differentiated HL60 cells is similar to that found in RA-treated cells. Herein we demonstrate that, unlike what is observed following RA treatment, the NADase activity of TPA differentiated cells associates with a 65 kDa glycosylphosphatidylinositol-anchored NADase.