| AATF inhibits aberrant production of amyloid beta peptide 1 42 by interacting directly with Par 4 . ^^^ AATF antagonizes apoptosis induced by Par 4 , suggesting that AATF might directly or indirectly participate in regulation of Par 4 activity . ^^^ We now report that AATF colocalizes with Par 4 in both cytoplasmic and nuclear compartments , and it interacts directly and selectively with Par 4 via the leucine zipper domain in neural cells . ^^^ Co expression of AATF completely blocked aberrant production and secretion of Abeta ( 1 42 ) induced by Par 4 , and AATF / Par 4 complex formation was essential for the inhibitory effect of AATF on aberrant Abeta secretion . ^^^ These results indicate that AATF is an endogenous antagonist of Par 4 activity and an effective inhibitor of aberrant Abeta production and secretion under apoptotic conditions . . ^^^ |