 In untransformed T lymphocytes, pp19/cofilin, a cytoplasmic actin-binding protein, undergoes dephosphorylation and nuclear translocation in response to costimulation through accessory receptors (e.g., CD2), but not following TCR/CD3 triggering.     ///    "In malignant T lymphoma cells, dephosphorylation and nuclear translocation of pp19/cofilin occur spontaneously through constitutive activation of a serine phosphatase. "    ///    Inhibition of constitutive serine phosphatase activity in T lymphoma cells results in phosphorylation of pp19/cofilin and induces apoptosis..     ///    "Moreover, lowering the intracellular pp19/cofilin concentrations by antisense-cofilin transfection results in reduced cloning efficiencies. "    ///    These findings provide support for the view that pp19/cofilin plays a critical role in the growth and survival of both untransformed and malignant T lymphocytes.. 