| Abstract: | A specific antibody was prepared against "abp38," a 38 kDa-dimer protein purified from mouse myeloid leukemia cells (M1 cells), that induce gelation of actin filaments in a K+-dependent manner. Immunochemically, the total content of abp38 in undifferentiated M1 cells was found to be 0.89% of the total protein (10.7 micrograms/10(7) cells). This content increased about 8-fold (89.5 micrograms/10(7) cells) after the M1 cells had differentiated into macrophages. When the cells before differentiation were extracted with Triton solution containing 150 mM KCl, almost all abp38 in the cytoskeleton was removed, whereas in cells after differentiation, amount of abp38 remaining in the cytoskeleton was 4.5 micrograms per 10(7) cells. The amount of cytoskeleton-bound abp38 of M1 cells and mouse peritoneal macrophages decreased with increase in K+ concentration in the extraction solution. Immunoreactive molecules against abp38 antibody were present in various tissues and cultured cell lines except for skeletal muscle and erythrocytes. Furthermore, actin binding protein with a molecular size of 38 kDa was found in bovine brain. These data suggest that abp38 is a ubiquitous protein present in various tissues and species. |
