Changes in contractile proteins during differentiation of myeloid leukemia cells. I. Polymerization of actin.
Quantitative and qualitative changes in cellular actin were followed during differentiation of a myeloid leukemia cell line, namely Ml, which was inducible with conditioned medium (CM). During 3 d of incubation with CM, when the Ml cells differentiated to macrophages and lost their mitotic activity, the actin content, F-actin ratio in total actin, and the actin synthesis showed an increase. A greater difference before and after differentiation was found in the ability of G-actin to polymerize. Actin harvested from CM-treated cells showed a greater ability to polymerize, depending on the increased concentration of MgCl2 and/or KCl and proteins, as compared with the actin from untreated Ml cells. Actin harvested from the Mml cell line, a macrophage line, had a particularly high polymerizability with or without CM treatment. In contrast, the actin from the D- subline, which is insensitive to CM, showed almost no polymerization.
D000199:Actins / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D002465:Cell Movement; D007942:Leukemia, Experimental; D008264:Macrophages / Q000166:cytology*; D008274:Magnesium / Q000494:pharmacology; D051379:Mice; D010587:Phagocytosis; D011108:Polymers; D011189:Potassium Chloride / Q000494:pharmacology
D000199:Actins; D011108:Polymers; D011189:Potassium Chloride; D008274:Magnesium