Calbindin-D28K in the nucleus of nerve growth factor-treated PC12 cells.

Calbindin-D28K (CB) is a calcium-binding protein found within a subset of neurons, which has been proposed to buffer intracellular calcium and to protect cells from calcium-induced neurodegeneration. The rat pheochromocytoma PC12 cell line has been an invaluable tool for studying neuronal development and characterizing the molecular actions of nerve growth factor (NGF). Using Western and RNAse protection analyses and immunocytochemical and cell fractionation techniques, we now report that NGF induces the expression of CB not only in the cytoplasm and neurites, but also within the nuclei of PC12 cells. These data indicate that PC12 cells can serve as a useful model system in which to study the functions of CB and the role of nuclear CB.