Protein phosphatase 2C alpha expression in normal human tissues: an immunohistochemical study

Protein phosphatase (PP2C alpha) is a member of the mammalian serine threon ine-specific protein phosphatases family. We produced monoclonal antibodies against the recombinant PP2C alpha and evaluated the immunoreactivity of n ormal human tissues. The reactivity was strong in normal skin, the digestiv e tract, lung, kidney, breast, prostate, endocrine glands, and brain, while it was moderate in the ovary, testis, and liver. Epithelial cells revealed high levels of PP2C alpha expression, but stromal cells, including fibrobl asts and endothelial cells, showed no or little PP2C alpha expression. Give n the broad reactivity in endocrine and secreting epithelial cells, we prop ose that PP2C alpha expression might contribute to secretory cell function.