The phosphoprotein p53 was trivially named after the apparent molecular mass it runs on SDS-PAGE, i.e., 53-kilodalton (kDa). Ever since its discovery in 1979 by several groups simultaneously, this extraordinary protein has captured the imagination of life scientists. p53 is likely the most extensively studied protein in cell biological research. To underscore its importance, p53 has been called a “cellular gatekeeper” [1] or “the guardian of the genome” [2], and for a long time researchers believed that p53 was the universal master switch that defined cancer onset and progression. However, this turned out to be not entirely true. Nonetheless, at least half of all cancer types carry aberrations in the p53 gene (TP53). p53 acts as a decision nodule that organizes the cell’s response to stress. Continue reading →