Predominant induction of gelsolin and actin-binding protein during myeloid differentiation.

Three actin-associated proteins, actin-binding protein, gelsolin, and profilin, influence gelation, solation, and polymerization, respectively, of actin in vitro. As assessed with specific cDNA probes and immunoaffinity reagents, a 7-50-fold increase in gelsolin, 3-5-fold increase in actin-binding protein, and less than 2-fold increases in actin and profilin protein and mRNA levels accompanied tetradecanoylphorbolacetate-induced differentiation of the myeloid cell lines U937 and HL60 into macrophage-like cells. Such induction in actin-binding protein or gelsolin did not occur in K562 cells, which respond minimally to tetradecanoylphorbolacetate, or following 1,25-dihydroxyvitamin D3-induced monocyte-like differentiation of U937, which results in a less motile phenotype. These observations suggest that increases in gelsolin and actin-binding protein are essential to the expression of many regulated motile functions which takes place during differentiation of myeloid cells.