CELL-SURFACE TRAFFICKING OF FAS - A RAPID MECHANISM OF P53-MEDIATED APOPTOSIS

p53 acts as a tumor suppressor by inducing both growth arrest and apop tosis. p53-induced apoptosis can occur without new RNA synthesis throu gh an unknown mechanism. In human vascular smooth muscle cells, p53 ac tivation transiently increased surface pas (CD95) expression by transp ort from the Golgi complex. Golgi disruption blocked both p53-induced surface Fas expression and apoptosis. p53 also induced Fas-FADD bindin g and transiently sensitized cells to Fas-induced apoptosis. In contra st, lpr and gld fibroblasts were resistant to p53-induced apoptosis. T hus, p53 can mediate apoptosis through pas transport from cytoplasmic stores.