Chronic myeloid leukemia granulocytes have lower amounts of cytoplasmic actin

Chronic myeloid leukemia (CML) granulocytes had earlier been shown to be defective in microfilament mediated phenomena such as chemotaxis and fluid phase pinocytosis when compared to normal granulocytes. The present studies were carried out to determine whether a quantitative alteration in actin or a change in isoform status could be responsible for some of the defects. Relative proportions of beta and gamma isoforms were found to be unaltered between normal and CML granulocytes. The amount of actin was significantly lower in CML cells. When the actin was expressed as percent of total protein in the granulocytes, it was found to be significantly lower in CML cells. The lower amount of actin may be responsible for some of the defects seen in CML cells.