Biosynthesis of the so-called “a” and “asialo” pathway glycosphingolipids is differentially regulated in murine myelogenous leukemia nfs60 cells

Regulation of “a” and “asialo” series ganglioside biosynthesis was analyzed. COS-1 cells expressing only GD1a showed high synthetic activities of GM3, GM2, GM1a, and GD1a, but little activity for GA2 synthesis. However, IL-3-dependent murine NFS60-I7, which has GM1b and GD1α, exhibited high synthetic activities of GM2, GM1a, and GD1a, but GM3 synthase was only 1/6 of COS-1 and GA2 synthetic activity was low. By contrast, IL-3 gene-transfected subline NFS60-H7 expressing GD1a in addition to GM1b and GD1α displayed up-regulated GM3 synthase and GA2 synthase activities, while GM2, GM1a, and GD1a synthase activities were in the same levels as in NFS60-I7 cells. Since GA2 synthetic activities were not parallel with GM2 synthase in the investigated machinery of ganglioside biosynthesis, it is strongly suggested that biosynthesis of and “asialo” series gangliosides is regulated differentially from each other in murine NFS60 cell lines.