A-431 nuclear extract
Active Motif's A-431 nuclear extract was prepared from cell cultures of the human epidermoid carcinoma A431 cell line. These cells are characterized by abnormally high levels of expression of epidermal growth factor receptor (EGFR), approximately 3 x 10E6/cell, on the cell surface and exhibits a biphasic response to varying concentrations of epidermal growth factor (EGF). Specifically, lower (pmol) concentrations of EGF stimulates cell growth while higher (nmol) concentrations inhibits cell growth and induces terminal differentiation. Therefore, these cells are commonly used as a positive control for EGFR expression and in studies of EGFR downstream signaling cascades. These cells are also highly responsive to mitogenic stimuli and are naturally devoid of p53 and so are also frequently used in cancer and cell cycle-associated studies.